View source for Attention deficit hyperactivity disorder

{{Short description|Neurodevelopmental disorder}}
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{{Use British English|date=September 2022}}
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{{Infobox medical condition
| name = Attention deficit hyperactivity disorder
| synonym = Attention-deficit/hyperactivity disorder<br />'''Formerly''': Attention deficit disorder (ADD), hyperkinetic disorder<ref name="AD">{{Cite journal |last1=Faraone |first1=Stephen V. |last2=Bellgrove |first2=Mark A. |last3=Brikell |first3=Isabell |last4=Cortese |first4=Samuele |last5=Hartman |first5=Catharina A. |last6=Hollis |first6=Chris |last7=Newcorn |first7=Jeffrey H. |last8=Philipsen |first8=Alexandra |last9=Polanczyk |first9=Guilherme V. |last10=Rubia |first10=Katya |last11=Sibley |first11=Margaret H. |last12=Buitelaar |first12=Jan K. |date=22 February 2024 |title=Attention-deficit/hyperactivity disorder |url=https://www.nature.com/articles/s41572-024-00495-0 |journal=[[Nature Reviews Disease Primers]] |language=en |volume=10 |issue=1 |page=11 |doi=10.1038/s41572-024-00495-0 |pmid=38388701 |issn=2056-676X}}</ref>
| image = ADHDNeuroanatomy.png
| image_upright = 1.2
| caption = ADHD arises from maldevelopment in brain regions such as the [[prefrontal cortex]], [[basal ganglia]] and [[anterior cingulate cortex]], which regulate the executive functions necessary for human self-regulation.<!-- NOTE that some of these brain regions mentioned, like the basal ganglia, include the striatum mentioned in the image -->
| alt = An image of the brain showcasing the underlying relationship between the neurology and neuropsychology of ADHD.
| field = {{hlist | [[Neuropsychiatry]] | [[pediatrics]]}}
| symptoms = {{hlist | [[Inattention]] | [[psychomotor agitation|hyperactivity]] | [[disinhibition]] | [[executive dysfunction]] | [[emotional dysregulation]] | [[impulsivity]] | impaired [[working memory]]}}
| complications =
| onset = Prior to age 12
| duration =
| causes = [[Genetic disorder|Genetic]] (inherited, [[de novo mutation|de novo]]) and to a lesser extent, [[environmental factors|environmental]] factors (exposure to biohazards during pregnancy, [[traumatic brain injury]])
| risks =
| diagnosis = Based on impairing symptoms after other possible causes have been ruled out
| differential = {{hlist | [[Bipolar disorder]] | [[cognitive disengagement syndrome]] | [[conduct disorder]] | [[major depressive disorder]] | [[autism spectrum disorder]] | [[oppositional defiant disorder]] | [[learning disorder]] | [[intellectual disability]] | [[anxiety disorder]]<ref>{{cite web |url=https://www.heysigmund.com/anxiety-and-adhd/ |title=Anxiety or ADHD? Why They Sometimes Look the Same and How to Tell the Difference | vauthors = Young K |website=Hey Sigmund |date=9 February 2017 |access-date=27 January 2023 |archive-date=26 January 2023 |archive-url=https://web.archive.org/web/20230126230720/https://www.heysigmund.com/anxiety-and-adhd/ |url-status=live}}</ref> | [[borderline personality disorder]] | [[fetal alcohol spectrum disorder]]}}
| prevention =
| treatment = {{hlist | Medication | [[psychotherapy]]}}
| medication = {{hlist | [[Stimulant]]s ([[methylphenidate]], [[amphetamine]]) | [[selective norepinephrine reuptake inhibitor]]s ([[atomoxetine]], [[viloxazine]]) | [[alpha-2A adrenergic receptor|α<sub>2A</sub>-adrenergic receptor]] [[alpha-adrenergic agonist|agonists]] ([[guanfacine]] XR, [[clonidine]] XR)}}
| prognosis =
| frequency = 0.8–1.5% (2019, using DSM-IV-TR and ICD-10)<ref name=GBD2019/>
| deaths =
}}
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'''Attention deficit hyperactivity disorder''' ('''ADHD''')<ref name="AD" /> is a [[neurodevelopmental disorder]] characterised by symptoms of [[inattention]], hyperactivity, [[impulsivity]], and [[emotional dysregulation]] that are excessive and pervasive, impairing in multiple contexts, and [[Developmental psychology|developmentally inappropriate]].{{refn|<ref name=DSM5>{{cite book |title=Diagnostic and Statistical Manual of Mental Disorders |publisher=American Psychiatric Publishing |url=https://archive.org/details/diagnosticstatis0005unse/page/58/mode/2up?q=attention+deficit |year=2013 |isbn=978-0-89042-555-8 |edition=5th |location=Arlington |pages=59–65}}</ref><ref name=DSM5TR>{{cite book |title=Diagnostic and Statistical Manual of Mental Disorders |edition=Fifth, Text Revision (DSM-5-TR) |title-link=DSM-5-TR |publisher=American Psychiatric Publishing |date=February 2022 |isbn=978-0-89042-575-6 |oclc=1288423302 |location=Washington, D.C.}}</ref><ref name="ICD-11" /><ref name="epa_consensus_2019" /><ref name="Faraone_2021">{{cite journal |vauthors=Faraone SV, Banaschewski T, Coghill D, Zheng Y, Biederman J, Bellgrove MA, Newcorn JH, Gignac M, Al Saud NM, Manor I, Rohde LA, Yang L, Cortese S, Almagor D, Stein MA, Albatti TH, Aljoudi HF, Alqahtani MM, Asherson P, Atwoli L, Bölte S, Buitelaar JK, Crunelle CL, Daley D, Dalsgaard S, Döpfner M, Espinet S, Fitzgerald M, Franke B, Gerlach M, Haavik J, Hartman CA, Hartung CM, Hinshaw SP, Hoekstra PJ, Hollis C, Kollins SH, Sandra Kooij JJ, Kuntsi J, Larsson H, Li T, Liu J, Merzon E, Mattingly G, Mattos P, McCarthy S, Mikami AY, Molina BS, Nigg JT, Purper-Ouakil D, Omigbodun OO, Polanczyk GV, Pollak Y, Poulton AS, Rajkumar RP, Reding A, Reif A, Rubia K, Rucklidge J, Romanos M, Ramos-Quiroga JA, Schellekens A, Scheres A, Schoeman R, Schweitzer JB, Shah H, Solanto MV, Sonuga-Barke E, Soutullo C, Steinhausen HC, Swanson JM, Thapar A, Tripp G, van de Glind G, van den Brink W, Van der Oord S, Venter A, Vitiello B, Walitza S, Wang Y |title=The World Federation of ADHD International Consensus Statement: 208 Evidence-based conclusions about the disorder |journal=[[Neuroscience & Biobehavioral Reviews]] |volume=128 |pages=789–818 |date=September 2021 |pmid=33549739 |pmc=8328933 |doi=10.1016/j.neubiorev.2021.01.022 |publisher=[[Elsevier BV]] |doi-access=free |issn=0149-7634}}</ref>}}<!-- quote=to a degree that is inconsistent with developmental level --> ADHD symptoms arise from [[executive dysfunction]].{{refn|<ref>{{cite journal |vauthors=Pievsky MA, McGrath RE |title=The Neurocognitive Profile of Attention-Deficit/Hyperactivity Disorder: A Review of Meta-Analyses |journal=Archives of Clinical Neuropsychology |volume=33 |issue=2 |pages=143–157 |date=March 2018 |pmid=29106438 |doi=10.1093/arclin/acx055 |doi-access=free}}</ref><ref>{{cite journal |vauthors=Schoechlin C, Engel RR |title=Neuropsychological performance in adult attention-deficit hyperactivity disorder: meta-analysis of empirical data |journal=Archives of Clinical Neuropsychology |volume=20 |issue=6 |pages=727–744 |date=August 2005 |pmid=15953706 |doi=10.1016/j.acn.2005.04.005}}</ref><ref name="Neuroplasticity 1"/><ref name="Joao P 2019">{{cite journal |vauthors=Hoogman M, Muetzel R, Guimaraes JP, Shumskaya E, Mennes M, Zwiers MP, Jahanshad N, Sudre G, Wolfers T, Earl EA, Soliva Vila JC, Vives-Gilabert Y, Khadka S, Novotny SE, Hartman CA, Heslenfeld DJ, Schweren LJ, Ambrosino S, Oranje B, de Zeeuw P, Chaim-Avancini TM, Rosa PG, Zanetti MV, Malpas CB, Kohls G, von Polier GG, Seitz J, Biederman J, Doyle AE, Dale AM, van Erp TG, Epstein JN, Jernigan TL, Baur-Streubel R, Ziegler GC, Zierhut KC, Schrantee A, Høvik MF, Lundervold AJ, Kelly C, McCarthy H, Skokauskas N, O'Gorman Tuura RL, Calvo A, Lera-Miguel S, Nicolau R, Chantiluke KC, Christakou A, Vance A, Cercignani M, Gabel MC, Asherson P, Baumeister S, Brandeis D, Hohmann S, Bramati IE, Tovar-Moll F, Fallgatter AJ, Kardatzki B, Schwarz L, Anikin A, Baranov A, Gogberashvili T, Kapilushniy D, Solovieva A, El Marroun H, White T, Karkashadze G, Namazova-Baranova L, Ethofer T, Mattos P, Banaschewski T, Coghill D, Plessen KJ, Kuntsi J, Mehta MA, Paloyelis Y, Harrison NA, Bellgrove MA, Silk TJ, Cubillo AI, Rubia K, Lazaro L, Brem S, Walitza S, Frodl T, Zentis M, Castellanos FX, Yoncheva YN, Haavik J, Reneman L, Conzelmann A, Lesch KP, Pauli P, Reif A, Tamm L, Konrad K, Oberwelland Weiss E, Busatto GF, Louza MR, Durston S, Hoekstra PJ, Oosterlaan J, Stevens MC, Ramos-Quiroga JA, Vilarroya O, Fair DA, Nigg JT, Thompson PM, Buitelaar JK, Faraone SV, Shaw P, Tiemeier H, Bralten J, Franke B |title=Brain Imaging of the Cortex in ADHD: A Coordinated Analysis of Large-Scale Clinical and Population-Based Samples |journal=[[The American Journal of Psychiatry]] |volume=176 |issue=7 |pages=531–542 |date=July 2019 |pmid=31014101 |pmc=6879185 |doi=10.1176/appi.ajp.2019.18091033}}</ref><ref name="Brown_2008">{{cite journal |vauthors=Brown TE |title=ADD/ADHD and Impaired Executive Function in Clinical Practice |journal=[[Current Psychiatry Reports]] |volume=10 |issue=5 |pages=407–411 |date=October 2008 |pmid=18803914 |doi=10.1007/s11920-008-0065-7 |s2cid=146463279}}</ref><ref name="Malenka pathways" /><ref name="Executive functions">{{cite journal |vauthors=Diamond A |title=Executive functions |journal=[[Annual Review of Psychology]] |volume=64 |pages=135–168 |year=2013 |pmid=23020641 |pmc=4084861 |doi=10.1146/annurev-psych-113011-143750 |quote={{abbr|EFs|executive functions}} and prefrontal cortex are the first to suffer, and suffer disproportionately, if something is not right in your life. They suffer first, and most, if you are stressed (Arnsten 1998, Liston et al. 2009, Oaten & Cheng 2005), sad (Hirt et al. 2008, von Hecker & Meiser 2005), lonely (Baumeister et al. 2002, Cacioppo & Patrick 2008, Campbell et al. 2006, Tun et al. 2012), sleep deprived (Barnes et al. 2012, Huang et al. 2007), or not physically fit (Best 2010, Chaddock et al. 2011, Hillman et al. 2008). Any of these can cause you to appear to have a disorder of EFs, such as ADHD, when you do not.}}</ref><ref name="Antshel_2014">{{cite book |vauthors=Antshel KM, Hier BO, Barkley RA |chapter=Executive Functioning Theory and ADHD |date=2014 |title=Handbook of Executive Functioning |pages=107–120 |veditors=Goldstein S, Naglieri JA |place=New York, NY |publisher=Springer |doi=10.1007/978-1-4614-8106-5_7 |isbn=978-1-4614-8106-5}}</ref>}}

Impairments resulting from deficits in self-regulation such as [[time management]], [[Cognitive inhibition|inhibition]], task initiation, and sustained attention<ref>{{Cite journal |last=Barkley |first=Russell A. |date=December 2002 |title=International Consensus Statement on ADHD |journal=[[Journal of the American Academy of Child and Adolescent Psychiatry]] |volume=41 |issue=12 |page=1389 |doi=10.1097/00004583-200212000-00001 |issn=0890-8567 |pmid=12447019}}</ref> can include poor professional performance, relationship difficulties, and numerous health risks,<ref name="Barkley_2011">{{Cite journal |vauthors=Barkley RA, Murphy KR |date=1 June 2011 |title=The Nature of Executive Function (EF) Deficits in Daily Life Activities in Adults with ADHD and Their Relationship to Performance on EF Tests |journal=[[Journal of Psychopathology and Behavioral Assessment]] |language=en |volume=33 |issue=2 |pages=137–158 |doi=10.1007/s10862-011-9217-x |issn=1573-3505}}</ref><ref name="fleming_et_al_2017">{{cite journal |vauthors=Fleming M, Fitton CA, Steiner MF, McLay JS, Clark D, King A, Mackay DF, Pell JP |title=Educational and Health Outcomes of Children Treated for Attention-Deficit/Hyperactivity Disorder |journal=[[JAMA Pediatrics]] |volume=171 |issue=7 |pages=e170691 |date=July 2017 |pmid=28459927 |pmc=6583483 |doi=10.1001/jamapediatrics.2017.0691}}</ref> collectively predisposing to a diminished [[Quality of life (healthcare)|quality of life]]<ref name="Coghill_2017" /> and a reduction in life expectancy.<ref name="Barkley & Fischer"/><ref name="Adverse_2022">{{cite journal |vauthors=Cattoi B, Alpern I, Katz JS, Keepnews D, Solanto MV |date=April 2022 |title=The Adverse Health Outcomes, Economic Burden, and Public Health Implications of Unmanaged Attention Deficit Hyperactivity Disorder (ADHD): A Call to Action Resulting from CHADD Summit, Washington, DC, October 17, 2019 |journal=[[Journal of Attention Disorders]] |volume=26 |issue=6 |pages=807–808 |doi=10.1177/10870547211036754 |pmid=34585995 |s2cid=238218526}}</ref> It is associated with other [[mental disorder]]s <!-- ADHD represents a mental disorder as well as a neurodevelopmental disorder. See the International Consensus Statement on ADHD (Faraone et al., 2021). -->as well as non-psychiatric disorders, which can cause additional impairment.<ref name="Faraone_2021" /><!-- For reference 6 before this comment, refrain from converting it into the other citation to the International Consensus Statement used in the article as this particular iteration has a "highlights" section which states "ADHD costs society hundreds of billions of dollars each year, worldwide". Both iterations indicate this with the research but the conclusion is more easily accessible in this one. (This statement is no longer in the article, but please do not change the source in case it is re-added)-->

While ADHD involves a lack of sustained attention to tasks,<ref name="Antshel_2014" /><ref name="Barkley_2011" /> inhibitory deficits also can lead to difficulty interrupting an already ongoing response pattern, manifesting in the perseveration of actions despite a change in context whereby the individual intends the termination of those actions.<ref>{{cite journal |url=https://psycnet.apa.org/record/1997-02112-004 |last=Barkley |first=R. A. |date=1997 |title=Behavioral inhibition, sustained attention, and executive functions: Constructing a unifying theory of ADHD |journal=Psychological Bulletin |volume=121 |issue=1 |pages=65–94 |doi=10.1037/0033-2909.121.1.65 |pmid=9000892 |url-access=subscription}}</ref><ref>{{cite journal |vauthors=Ayers-Glassey S, MacIntyre PD |date=September 2021 |title=Investigating emotion dysregulation and the perseveration-and flow-like characteristics of ADHD hyperfocus in Canadian undergraduate students. |journal=Psychology of Consciousness: Theory, Research, and Practice |volume=11 |issue=2 |pages=234–251 |doi=10.1037/cns0000299}}</ref> This symptom is known colloquially as [[hyperfocus]]<ref name="Groen_et_al_2020"/> and is related to risks such as [[addiction]]<ref name="use">{{cite journal |vauthors=Long Y, Pan N, Ji S, Qin K, Chen Y, Zhang X, He M, Suo X, Yu Y, Wang S, Gong Q |date=September 2022 |title=Distinct brain structural abnormalities in attention-deficit/hyperactivity disorder and substance use disorders: A comparative meta-analysis |journal=Translational Psychiatry |volume=12 |issue=1 |article-number=368 |doi=10.1038/s41398-022-02130-6 |pmc=9448791 |pmid=36068207}}</ref><ref name="Ishii_et_al_2023">{{cite journal |vauthors=Ishii S, Takagi S, Kobayashi N, Jitoku D, Sugihara G, Takahashi H |date=16 March 2023 |title=Hyperfocus symptom and internet addiction in individuals with attention-deficit/hyperactivity disorder trait |journal=Frontiers in Psychiatry |volume=14 |article-number=1127777 |doi=10.3389/fpsyt.2023.1127777 |pmc=10061009 |pmid=37009127 |doi-access=free}}</ref> and types of offending behaviour.<ref>{{Cite journal |last1=Worthington |first1=Rachel |last2=Wheeler |first2=Suzanne |date=1 January 2023 |title=Hyperfocus and offending behaviour: a systematic review |url=https://www.emerald.com/insight/content/doi/10.1108/jfp-01-2022-0005/full/html |journal=The Journal of Forensic Practice |volume=25 |issue=3 |pages=185–200 |doi=10.1108/JFP-01-2022-0005 |issn=2050-8794}}</ref> ADHD can be difficult to tell apart from other conditions.<ref name="Executive functions"/><ref name="Coghill_2017" /> ADHD represents the extreme lower end of the continuous dimensional trait (bell curve) of executive functioning and self-regulation, which is supported by twin, brain imaging and molecular genetic studies.{{refn|<ref name="Joao P 2019" /><ref name="Antshel_2014" /><ref>{{cite journal |vauthors=Larsson H, Anckarsater H, Råstam M, Chang Z, Lichtenstein P |title=Childhood attention-deficit hyperactivity disorder as an extreme of a continuous trait: a quantitative genetic study of 8,500 twin pairs |journal=[[Journal of Child Psychology and Psychiatry|Journal of Child Psychology and Psychiatry, and Allied Disciplines]] |volume=53 |issue=1 |pages=73–80 |date=January 2012 |pmid=21923806 |doi=10.1111/j.1469-7610.2011.02467.x}}</ref><ref>{{cite journal |vauthors=Lee SH, Ripke S, Neale BM, Faraone SV, Purcell SM, Perlis RH, Mowry BJ, Thapar A, Goddard ME, Witte JS, Absher D, Agartz I, Akil H, Amin F, Andreassen OA, Anjorin A, Anney R, Anttila V, Arking DE, Asherson P, Azevedo MH, Backlund L, Badner JA, Bailey AJ, Banaschewski T, Barchas JD, Barnes MR, Barrett TB, Bass N, Battaglia A, Bauer M, Bayés M, Bellivier F, Bergen SE, Berrettini W, Betancur C, Bettecken T, Biederman J, Binder EB, Black DW, Blackwood DH, Bloss CS, Boehnke M, Boomsma DI, Breen G, Breuer R, Bruggeman R, Cormican P, Buccola NG, Buitelaar JK, Bunney WE, Buxbaum JD, Byerley WF, Byrne EM, Caesar S, Cahn W, Cantor RM, Casas M, Chakravarti A, Chambert K, Choudhury K, Cichon S, Cloninger CR, Collier DA, Cook EH, Coon H, Cormand B, Corvin A, Coryell WH, Craig DW, Craig IW, Crosbie J, Cuccaro ML, Curtis D, Czamara D, Datta S, Dawson G, Day R, De Geus EJ, Degenhardt F, Djurovic S, Donohoe GJ, Doyle AE, Duan J, Dudbridge F, Duketis E, Ebstein RP, Edenberg HJ, Elia J, Ennis S, Etain B, Fanous A, Farmer AE, Ferrier IN, Flickinger M, Fombonne E, Foroud T, Frank J, Franke B, 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Kelsoe JR, Sklar P, Daly MJ, O'Donovan MC, Craddock N, Sullivan PF, Smoller JW, Kendler KS, Wray NR |title=Genetic relationship between five psychiatric disorders estimated from genome-wide SNPs |journal=[[Nature Genetics]] |volume=45 |issue=9 |pages=984–994 |date=September 2013 |pmid=23933821 |pmc=3800159 |doi=10.1038/ng.2711}}</ref><ref>{{cite journal |vauthors=Cecil CA, Nigg JT |title=Epigenetics and ADHD: Reflections on Current Knowledge, Research Priorities and Translational Potential |journal=Molecular Diagnosis & Therapy |volume=26 |issue=6 |pages=581–606 |date=November 2022 |pmid=35933504 |pmc=7613776 |doi=10.1007/s40291-022-00609-y}}</ref><ref>{{cite journal |vauthors=Nigg JT, Sibley MH, Thapar A, Karalunas SL |title=Development of ADHD: Etiology, Heterogeneity, and Early Life Course |journal=[[Annual Review of Developmental Psychology]] |volume=2 |issue=1 |pages=559–583 |date=December 2020 |pmid=34368774 |pmc=8336725 |doi=10.1146/annurev-devpsych-060320-093413}}</ref><ref name="Barkley_2011a">{{cite book |vauthors=Barkley RA |date=2011 |chapter=Attention-deficit/hyperactivity disorder, self-regulation, and executive functioning. |veditors=Vohs KD, Baumeister RF |title=Handbook of self-regulation: Research, theory, and applications |edition=2nd |pages=551–563 |publisher=[[Guilford Press]] |chapter-url=https://psycnet.apa.org/record/2010-24692-030}}</ref><ref name="Brown_2009">{{Cite journal |vauthors=Brown TE |date=March 2009 |title=ADD/ADHD and impaired executive function in clinical practice |journal=Current Attention Disorders Reports |language=en |volume=1 |issue=1 |pages=37–41 |doi=10.1007/s12618-009-0006-3 |issn=1943-457X}}</ref>}}<!-- These references need to be bundled together --><!-- For citation Nigg and Cecil (above for continuous dimensional trait), 2022 see Figure 1. -->

<!--Causes, diagnosis and epidemiology -->
The precise causes of ADHD are unknown in most individual cases.<ref name=nimh/><ref>{{cite journal |vauthors=Franke B, Michelini G, Asherson P, Banaschewski T, Bilbow A, Buitelaar JK, Cormand B, Faraone SV, Ginsberg Y, Haavik J, Kuntsi J, Larsson H, Lesch KP, Ramos-Quiroga JA, Réthelyi JM, Ribases M, Reif A |title=Live fast, die young? A review on the developmental trajectories of ADHD across the lifespan |journal=European Neuropsychopharmacology |volume=28 |issue=10 |pages=1059–1088 |date=October 2018 |pmid=30195575 |pmc=6379245 |doi=10.1016/j.euroneuro.2018.08.001}}</ref> Meta-analyses have shown that the disorder is primarily genetic with a heritability rate of 70–80%,<ref name="HD" /><ref>{{Cite journal |last1=Leclercq |first1=Sébastien |last2=Bleazard |first2=Ryan |last3=Renisley |first3=Malcolm |date=21 April 2025 |title=The Aetiology of Attention-Deficit/Hyperactivity Disorder: Key Insights from Our Systematic Review |url=https://sciety.org/articles/activity/10.31234/osf.io/5dh8s_v2 |access-date=14 May 2025 |website=Sciety |language=en |doi=10.31234/osf.io/5dh8s_v2}}</ref><ref>{{Cite journal |last1=Grimm |first1=Oliver |last2=Kranz |first2=Thorsten M. |last3=Reif |first3=Andreas |date=27 February 2020 |title=Genetics of ADHD: What Should the Clinician Know? |journal=Current Psychiatry Reports |language=en |volume=22 |issue=4 |page=18 |doi=10.1007/s11920-020-1141-x |issn=1535-1645 |pmc=7046577 |pmid=32108282}}</ref> where risk factors are highly accumulative.<ref>{{cite journal |vauthors=Faraone SV, Asherson P, Banaschewski T, Biederman J, Buitelaar JK, Ramos-Quiroga JA, Rohde LA, Sonuga-Barke EJ, Tannock R, Franke B |title=Attention-deficit/hyperactivity disorder |journal=[[Nature Reviews Disease Primers]] |volume=1 |article-number=15020 |date=August 2015 |pmid=27189265 |doi=10.1038/nrdp.2015.20 |s2cid=7171541 |url=https://repository.ubn.ru.nl//bitstream/handle/2066/291735/291735.pdf}}</ref> The environmental risks are not related to social or familial factors;<ref>{{cite journal |url=https://psycnet.apa.org/record/2010-02209-001 |vauthors=Nikolas, MA, Burt, SA |date=2010 |title=Genetic and environmental influences on ADHD symptom dimensions of inattention and hyperactivity: A meta-analysis |journal=[[Journal of Abnormal Psychology]] |volume=119 |issue=1 |pages=1–17 |doi=10.1037/a0018010 |pmid=20141238 |url-access=subscription}}</ref><ref name="Intergenerational">{{Cite web |date=2022 |title=Intergenerational transmission of ADHD behaviors: More evidence for heritability than life history theor |url=https://europepmc.org/article/ppr/ppr531866#impact |access-date=1 October 2024 |website=europepmc.org}}</ref><ref name=hl>{{Cite journal |last1=Larsson |first1=Henrik |last2=Chang |first2=Zheng |last3=D'Onofrio |first3=Brian M. |last4=Lichtenstein |first4=Paul |date=July 2014 |title=The heritability of clinically diagnosed Attention-Deficit/Hyperactivity Disorder across the life span |journal=Psychological Medicine |volume=44 |issue=10 |pages=2223–2229 |doi=10.1017/S0033291713002493 |issn=0033-2917 |pmc=4071160 |pmid=24107258}}</ref> they exert their effects very early in life, in the prenatal or early postnatal period.<ref name="Faraone_2021" /> However, in rare cases, ADHD can be caused by a single event<!-- Keep 'event' as it clarifies the fact that the environmental causes are entirely due to unique (non-shared) events and not the rearing social environment, as established by e.g. meta-analyses of twin studies --> including [[traumatic brain injury]],<ref name="HD">{{cite journal |url=https://pure.rug.nl/ws/portalfiles/portal/1124067910/s41572-024-00495-0.pdf |vauthors=Faraone, SV, Bellgrove, MA, Brikell, I, Cortese, S, Hartman, CA, Hollis, C, Newcorn, JH, Philipsen, A, Polanczyk, GV, Rubia, K, Sibley, MH, Buitelaar, JK |date=2024 |title=Attention–deficit/hyperactivity disorder |journal=Nature Reviews. Disease Primers |volume=10 |issue=1 |article-number=11 |doi=10.1038/s41572-024-00495-0 |pmid=38388701}}</ref> exposure to biohazards during pregnancy,<ref name = "Faraone_2021" /> or a major genetic mutation.<ref name="Faraone_2019">{{cite journal |vauthors=Faraone SV, Larsson H |title=Genetics of attention deficit hyperactivity disorder |journal=[[Molecular Psychiatry]] |volume=24 |issue=4 |pages=562–575 |date=April 2019 |pmid=29892054 |pmc=6477889 |doi=10.1038/s41380-018-0070-0 |publisher=[[Nature Research]] |author1-link=Stephen Faraone}}</ref> As it is a neurodevelopmental disorder, there is no biologically distinct adult-onset ADHD except for when ADHD occurs after traumatic brain injury.<ref name="Faraone_2021"/><ref name="Faraone_2016">{{cite journal |vauthors=Faraone SV, Biederman J |title=Can Attention-Deficit/Hyperactivity Disorder Onset Occur in Adulthood? |journal=[[JAMA Psychiatry]] |volume=73 |issue=7 |pages=655–656 |date=July 2016 |pmid=27191055 |doi=10.1001/jamapsychiatry.2016.0400}}</ref>

{{TOC limit}}

==Signs and symptoms==
Inattention, hyperactivity (restlessness in adults), disruptive behaviour, and impulsivity are common in ADHD.<ref name=cdc2016facts/><ref name="National Institute of Mental Health_2023">{{Cite web |title=Attention-Deficit/Hyperactivity Disorder |url=https://www.nimh.nih.gov/health/topics/attention-deficit-hyperactivity-disorder-adhd |access-date=2 January 2024 |website=National Institute of Mental Health |date=September 2023}}</ref><ref name="National Institute of Mental Health">{{Cite web |title=Attention-Deficit/Hyperactivity Disorder in Adults: What You Need to Know |url=https://www.nimh.nih.gov/health/publications/adhd-what-you-need-to-know |access-date=2 January 2024 |website=[[National Institute of Mental Health]]}}</ref> Academic difficulties are frequent, as are problems with relationships.<ref name="National Institute of Mental Health_2023" /><ref name="National Institute of Mental Health" /><ref name="ICSI2012">{{cite web |date=Mar 2012 |publisher=National Guideline Clearinghous |title=Diagnosis and management of attention deficit hyperactivity disorder in primary care for school-age children and adolescents |url=http://guidelines.gov/content.aspx?f=rss&id=36812 |archive-url=https://web.archive.org/web/20130301124247/http://guidelines.gov/content.aspx?f=rss&id=36812 |archive-date=1 March 2013 |access-date=10 October 2012 |page=79 |vauthors = Dobie C, Donald WB, Hanson M, Heim C, Huxsahl J, Karasov R, Kippes C, Neumann A, Spinner P, Staples T, Steiner L}}</ref> The signs and symptoms can be difficult to define, as it is hard to draw a line at where normal levels of inattention, hyperactivity, and impulsivity end and significant levels requiring interventions begin.<ref name ="Ramsay_2007">{{cite book |vauthors=Ramsay JR |title=Cognitive behavioral therapy for adult ADHD |publisher=Routledge |year=2007 |isbn=978-0-415-95501-0 |pages=4, 25–26}}</ref>

According to the [[DSM-5|fifth edition of the ''Diagnostic and Statistical Manual of Mental Disorders'']] (DSM-5) and its text revision ([[DSM-5-TR]]), symptoms must be present for six months or more to a degree that is much greater than others of the [[age appropriate|same age]].<ref name=DSM5/><ref name=DSM5TR/> This requires at least six symptoms of either inattention or hyperactivity/impulsivity for those under 17 and at least five symptoms for those 17 years or older.<ref name=DSM5/><ref name=DSM5TR/> The symptoms must be present in at least two settings (e.g., social, school, work, or home), and must directly interfere with or reduce quality of functioning.<ref name=DSM5/> Additionally, several symptoms must have been present before age 12 as per DSM-5 criteria.<ref name=DSM5TR/><ref name=DSM5/><ref>{{cite journal |vauthors=Epstein JN, Loren RE |title=Changes in the Definition of ADHD in DSM-5: Subtle but Important |journal=Neuropsychiatry |volume=3 |issue=5 |pages=455–458 |date=October 2013 |pmid=24644516 |pmc=3955126 |doi=10.2217/npy.13.59}}</ref> However, research indicates the age of onset should not be interpreted as a prerequisite for diagnosis given contextual exceptions.<ref name="Faraone_2016" />

=== <span class="anchor" id="ADHD-PH"></span> Presentations ===
<!-- This Anchor tag serves to provide a permanent target for incoming section links. Please do not remove it, nor modify it, except to add another appropriate anchor. If you modify the section title, please anchor the old title. It is always best to anchor an old section header that has been changed so that links to it will not be broken. See [[Template:Anchor]] for details. This template is {{subst:Anchor comment}} -->
ADHD is divided into three primary presentations:<ref name=DSM5TR/><ref name="Ramsay_2007" />
* [[Attention deficit hyperactivity disorder predominantly inattentive|predominantly inattentive]] (ADHD-PI or ADHD-I)
* predominantly hyperactive-impulsive (ADHD-PH or ADHD-HI)
* combined presentation (ADHD-C).

The table "Symptoms" lists the symptoms for ADHD-I and ADHD-HI from two major classification systems. Symptoms which can be better explained by another psychiatric or medical condition which an individual has are not considered to be a symptom of ADHD for that person. In DSM-5, subtypes were discarded and reclassified as presentations of the disorder that change over time.
{| class="wikitable"
|+Symptoms
!Presentations
!width=45%|{{abbr|DSM-5|Diagnostic and Statistical Manual, 5th Edition}} and {{abbr|DSM-5-TR|Diagnostic and Statistical Manual, 5th Edition, Text Revision}} symptoms<ref name=DSM5/><ref name=DSM5TR/>
!width=45%|{{abbr|ICD-11|International Classification of Diseases |edition=11th}} symptoms<ref name="ICD-11" />
|-
|Inattention
|<!-- DSM-5 -->Six or more of the following symptoms in children, and five or more in adults, excluding situations where these symptoms are better explained by another psychiatric or medical condition:
* Frequently overlooks details or makes careless mistakes
* Often has difficulty maintaining focus on one task or play activity
* Often appears not to be listening when spoken to, including when there is no obvious distraction
* Frequently does not finish following instructions, failing to complete tasks
* Often struggles to organise tasks and activities, to meet deadlines, and to keep belongings in order
* Is frequently reluctant to engage in tasks which require sustained attention
* Frequently loses items required for tasks and activities
* Is frequently easily distracted by extraneous stimuli, including thoughts in adults and older teenagers
* Often forgets daily activities, or is forgetful while completing them.
|<!-- ICD-11 -->Multiple symptoms of inattention that directly negatively impact occupational, academic or social functioning. Symptoms may not be present when engaged in highly stimulating tasks with frequent rewards. Symptoms are generally from the following clusters:
* Struggles to maintain focus on tasks that are not highly stimulating/rewarding or that require continuous effort; details are often missed, and careless mistakes are frequent in school and work tasks; tasks are often abruptly abandoned in favour of another before they are completed.
* Easily distracted (including by own thoughts); may not listen when spoken to; frequently appears to be lost in thought
* Often loses things; is forgetful and disorganised in daily activities.

The individual may also meet the criteria for hyperactivity-impulsivity, but the inattentive symptoms are predominant.
|-
|Hyperactivity-Impulsivity
|<!-- DSM-5 -->Six or more of the following symptoms in children, and five or more in adults, excluding situations where these symptoms are better explained by another psychiatric or medical condition:
* Is often fidgeting or squirming in seat
* Frequently has trouble sitting still during dinner, class, in meetings, etc.
* Frequently runs around or climbs in inappropriate situations. In adults and teenagers, this may be present only as restlessness.
* Often cannot quietly engage in leisure activities or play
* Frequently seems to be "on the go" or appears uncomfortable when not in motion
* Often talks excessively
* Often answers a question before it is finished, or finishes people's sentences
* Often struggles to wait their turn, including waiting in lines
* Frequently interrupts or intrudes, including into others' conversations or activities, or by using people's things without asking.
|<!-- ICD-11 -->Multiple symptoms of hyperactivity/impulsivity that directly negatively impact occupational, academic or social functioning. Typically, these tend to be most apparent in environments with structure or which require self-control. Symptoms are generally from the following clusters:
* Excessive motor activity; struggles to sit still, often leaving their seat; prefers to run about; in younger children, will fidget when attempting to sit still; in adolescents and adults, a sense of physical restlessness or discomfort with being quiet and still.
* Talks too much; struggles to quietly engage in activities.
* Blurts out answers or comments; struggles to wait their turn in conversation, games, or activities; will interrupt or intrude on conversations or games.
* A lack of forethought or consideration of consequences when making decisions or taking action, instead tending to act immediately (e.g., physically dangerous behaviours including reckless driving; impulsive decisions).

The individual may also meet the criteria for inattention, but the hyperactive-impulsive symptoms are predominant.
|-
|Combined
|<!-- DSM-5 -->Meet the criteria for both inattentive and hyperactive-impulsive ADHD.
|<!-- ICD-11 -->Criteria are met for both inattentive and hyperactive-impulsive ADHD, with neither clearly predominating.
|}

Girls and women with ADHD tend to display fewer hyperactivity and impulsivity symptoms but more symptoms of inattention and distractibility.<ref>{{cite journal |vauthors=Gershon J |title=A meta-analytic review of gender differences in ADHD |journal=[[Journal of Attention Disorders]] |volume=5 |issue=3 |pages=143–154 |date=January 2002 |pmid=11911007 |doi=10.1177/108705470200500302 |s2cid=8076914}}</ref>

Symptoms are expressed differently and more subtly as the individual ages.<ref name="Kooij_2010">{{cite journal |vauthors=Kooij SJ, Bejerot S, Blackwell A, Caci H, Casas-Brugué M, Carpentier PJ, Edvinsson D, Fayyad J, Foeken K, Fitzgerald M, Gaillac V, Ginsberg Y, Henry C, Krause J, Lensing MB, Manor I, Niederhofer H, Nunes-Filipe C, Ohlmeier MD, Oswald P, Pallanti S, Pehlivanidis A, Ramos-Quiroga JA, Rastam M, Ryffel-Rawak D, Stes S, Asherson P |title=European consensus statement on diagnosis and treatment of adult ADHD: The European Network Adult ADHD |journal=[[BMC Psychiatry]] |volume=10 |issue=67 |article-number=67 |date=September 2010 |pmid=20815868 |pmc=2942810 |doi=10.1186/1471-244X-10-67 |doi-access=free}}</ref>{{rp|6|quote=Whereas the core symptoms of hyperactivity, impulsivity and inattention, are well characterised in children, these symptoms may have different and more subtle expressions in adult life.}} Hyperactivity tends to become less overt with age and turns into inner restlessness, difficulty relaxing or remaining still, talkativeness or constant mental activity in teens and adults with ADHD.<ref name="Kooij_2010"/>{{rp|pp=6–7 |quote=For instance, where children with ADHD may run and climb excessively, or have difficulty in playing or engaging quietly in leisure activities, adults with ADHD are more likely to experience inner restlessness, inability to relax, or over talkativeness. Hyperactivity may also be expressed as excessive fidgeting, the inability to sit still for long in situations when sitting is expected (at the table, in the movie, in church or at symposia), or being on the go all the time. ... For example, physical overactivity in children could be replaced in adulthood by constant mental activity, feelings of restlessness and difficulty engaging in sedentary activities.}} Impulsivity in adulthood may appear as thoughtless behaviour, impatience, irresponsible spending and sensation-seeking behaviours,<ref name="Kooij_2010"/>{{rp|6|quote=Impulsivity may be expressed as impatience, acting without thinking, spending impulsively, starting new jobs and relationships on impulse, and sensation seeking behaviours.}} while inattention may appear as becoming easily bored, difficulty with organisation, remaining on task and making decisions, and sensitivity to stress.<ref name="Kooij_2010"/>{{rp|6|quote=Inattention often presents as distractibility, disorganization, being late, being bored, need for variation, difficulty making decisions, lack of overview, and sensitivity to stress.}}

====Characteristics in childhood====
Difficulties managing anger are more common in children with ADHD,<ref>{{cite web |title=ADHD Anger Management Directory |publisher=Webmd.com |url=http://www.webmd.com/add-adhd/adhd-anger-management-directory |access-date=17 January 2014 |url-status=live |archive-date=5 November 2013 |archive-url=https://web.archive.org/web/20131105032151/http://www.webmd.com/add-adhd/adhd-anger-management-directory}}</ref> as are delays in [[communication disorder|speech, language]] and motor development.<ref name="ICD10"/><ref name="pmid22201208">{{cite journal |vauthors=Bellani M, Moretti A, Perlini C, Brambilla P |title=Language disturbances in ADHD |journal=Epidemiology and Psychiatric Sciences |volume=20 |issue=4 |pages=311–315 |date=December 2011 |pmid=22201208 |doi=10.1017/S2045796011000527 |doi-access=free}}</ref> Poorer [[handwriting]] is more common in children with ADHD.<ref name="Racine_2008">{{cite journal |vauthors=Racine MB, Majnemer A, Shevell M, Snider L |title=Handwriting performance in children with attention deficit hyperactivity disorder (ADHD) |journal=[[Journal of Child Neurology]] |volume=23 |issue=4 |pages=399–406 |date=April 2008 |pmid=18401033 |doi=10.1177/0883073807309244 |s2cid=206546871}}</ref> Poor handwriting can be a symptom of ADHD in itself due to decreased attentiveness. When this is a pervasive problem, it may also be attributable to [[dyslexic|dyslexia]]<ref>{{cite journal |vauthors=Peterson RL, Pennington BF |title=Developmental dyslexia |journal=[[The Lancet]] |volume=379 |issue=9830 |pages=1997–2007 |date=May 2012 |pmid=22513218 |pmc=3465717 |doi=10.1016/S0140-6736(12)60198-6}}</ref><ref>{{cite journal |vauthors=Sexton CC, Gelhorn HL, Bell JA, Classi PM |title=The co-occurrence of reading disorder and ADHD: epidemiology, treatment, psychosocial impact, and economic burden |journal=[[Journal of Learning Disabilities]] |volume=45 |issue=6 |pages=538–564 |date=November 2012 |pmid=21757683 |doi=10.1177/0022219411407772 |s2cid=385238}}</ref> or [[dysgraphia]]. There is significant overlap in the symptomatologies of ADHD, dyslexia, and dysgraphia,<ref name="Nicolson_2011">{{cite journal |vauthors=Nicolson RI, Fawcett AJ |title=Dyslexia, dysgraphia, procedural learning and the cerebellum |journal=Cortex; A Journal Devoted to the Study of the Nervous System and Behavior |volume=47 |issue=1 |pages=117–127 |date=January 2011 |pmid=19818437 |doi=10.1016/j.cortex.2009.08.016 |s2cid=32228208}}</ref> and 3 in 10 people diagnosed with dyslexia experience co-occurring ADHD.<ref>{{cite web |url=https://www.webmd.com/add-adhd/adhd-dyslexia-tell-apart |title=Dyslexia and ADHD |access-date=19 May 2022 |archive-date=21 February 2023 |archive-url=https://web.archive.org/web/20230221112159/https://www.webmd.com/add-adhd/adhd-dyslexia-tell-apart |url-status=live}}</ref> Although it causes significant difficulty, many children with ADHD have an attention span equal to or greater than that of other children for tasks and subjects they find interesting.<ref name="Walitza_2012">{{cite journal |vauthors=Walitza S, Drechsler R, Ball J |title= [The school child with ADHD] |language=de |journal=Therapeutische Umschau |volume=69 |issue=8 |pages=467–473 |date=August 2012 |pmid=22851461 |doi=10.1024/0040-5930/a000316 |trans-title=The school child with ADHD}}</ref>

===Emotional dysregulation===
Although not listed as an official symptom, [[emotional dysregulation]] or [[mood lability]] is generally understood to be a common symptom of ADHD.<ref name="Retz_2012">{{cite journal |vauthors=Retz W, Stieglitz RD, Corbisiero S, Retz-Junginger P, Rösler M |title=Emotional dysregulation in adult ADHD: What is the empirical evidence? |journal=Expert Review of Neurotherapeutics |volume=12 |issue=10 |pages=1241–1251 |date=October 2012 |pmid=23082740 |doi=10.1586/ern.12.109 |s2cid=207221320}}</ref><ref>{{cite journal |vauthors=Faraone SV, Rostain AL, Blader J, Busch B, Childress AC, Connor DF, Newcorn JH |title=Practitioner Review: Emotional dysregulation in attention-deficit/hyperactivity disorder - implications for clinical recognition and intervention |journal=[[Journal of Child Psychology and Psychiatry|Journal of Child Psychology and Psychiatry, and Allied Disciplines]] |volume=60 |issue=2 |pages=133–150 |date=February 2019 |pmid=29624671 |doi=10.1111/jcpp.12899}}</ref><ref>{{cite journal |vauthors=Shaw P, Stringaris A, Nigg J, Leibenluft E |title=Emotion dysregulation in attention deficit hyperactivity disorder |journal=[[The American Journal of Psychiatry]] |volume=171 |issue=3 |pages=276–293 |date=March 2014 |pmid=24480998 |pmc=4282137 |doi=10.1176/appi.ajp.2013.13070966}}</ref><ref name="Kooij_2010"/>{{rp|6|quote=In addition, many adults with ADHD experience lifetime mood lability with frequent highs and lows, and short-fuse temper outburst.}}

===Relationship difficulties===
People with ADHD of all ages are more likely to have problems with [[social skills]], such as social interaction and forming and maintaining friendships.<ref>{{cite journal |vauthors=Carpenter Rich E, Loo SK, Yang M, Dang J, Smalley SL |title=Social functioning difficulties in ADHD: association with PDD risk |journal=[[Clinical Child Psychology and Psychiatry]] |volume=14 |issue=3 |pages=329–344 |date=July 2009 |pmid=19515751 |pmc=2827258 |doi=10.1177/1359104508100890}}</ref> This is true for all presentations. About half of children and adolescents with ADHD experience [[social rejection]] by their peers compared to 10–15% of non-ADHD children and adolescents. People with attention deficits are prone to having difficulty processing verbal and nonverbal language which can negatively affect social interaction. They may also drift off during conversations, miss social cues, and have trouble learning social skills.<ref>{{cite journal |vauthors=Coleman WL |title=Social competence and friendship formation in adolescents with attention-deficit/hyperactivity disorder |journal=Adolescent Medicine |volume=19 |issue=2 |pages=278–99, x |date=August 2008 |pmid=18822833}}</ref>

===Hyperfocus===
{{See also|Hyperfocus}}
An association between ADHD and hyperfocus, a state characterised by intense and narrow concentration on a specific stimulus, object or task for a prolonged period of time,<ref name="Chutko_et_al_2024">{{cite journal |last1=Chutko |first1=L. S. |last2=Surushkina |first2=S. Yu. |last3=Yakovenko |first3=E. A. |last4=Cherednichenko |first4=D. V. |title=Attention Deficit Hyperactivity Disorder in Adults |journal=Neuroscience and Behavioral Physiology |date=June 2024 |volume=54 |issue=5 |pages=644–649 |doi=10.1007/s11055-024-01643-5}}</ref> has been widely reported in the [[Popular science|popular science press]] and media.<ref name="Groen_et_al_2020" >{{cite journal |last1=Groen |first1=Yvonne |last2=Priegnitz |first2=Ulrike |last3=Fuermaier |first3=Anselm B. M. |last4=Tucha |first4=Lara |last5=Tucha |first5=Oliver |last6=Aschenbrenner |first6=Steffen |last7=Weisbrod |first7=Matthias |last8=Garcia Pimenta |first8=Miguel |title=Testing the relation between ADHD and hyperfocus experiences |journal=Research in Developmental Disabilities |date=1 December 2020 |volume=107 |issue=103789 |article-number=103789 |doi=10.1016/j.ridd.2020.103789 |doi-access = free |pmid=33126147 |issn=0891-4222}}</ref> The phenomenon generally occurs when an individual is engaged in activities they find highly interesting, or which provide instant gratification, such as video games or online chatting.<ref name="epa_consensus_2019" /> Hyperfocus is not a recognised symptom of ADHD in diagnostic manuals, but is frequently referred to as a symptom of ADHD in academic literature<ref name="Ashinoff_Abu_Akel_2019">{{cite journal |vauthors=Ashinoff BK, Abu-Akel A |date=February 2021 |title=Hyperfocus: the forgotten frontier of attention |journal=Psychological Research |volume=85 |issue=1 |pages=1–19 |doi=10.1007/s00426-019-01245-8 |pmc=7851038 |pmid=31541305}}</ref> and commonly reported in patients with ADHD in clinical practice.<ref name="Groen_et_al_2020" /> There is a lack of research into hyperfocus in ADHD.<ref name="Ashinoff_Abu_Akel_2019" /> Studies in 2016, 2019 and 2024 found that individuals with ADHD diagnoses or self-reported ADHD symptoms experience hyperfocus more often,<ref>{{cite journal |last1=Ozel-Kizil |first1=Erguvan Tugba |last2=Kokurcan |first2=Ahmet |last3=Aksoy |first3=Umut Mert |last4=Kanat |first4=Bilgen Bicer |last5=Sakarya |first5=Direnc |last6=Bastug |first6=Gulbahar |last7=Colak |first7=Burcin |last8=Altunoz |first8=Umut |last9=Kirici |first9=Sevinc |last10=Demirbas |first10=Hatice |last11=Oncu |first11=Bedriye |title=Hyperfocusing as a dimension of adult attention deficit hyperactivity disorder |journal=Research in Developmental Disabilities |date=1 December 2016 |volume=59 |pages=351–358 |doi=10.1016/j.ridd.2016.09.016 |pmid=27681531}}</ref><ref>{{cite journal |last1=Hupfeld |first1=Kathleen E. |last2=Abagis |first2=Tessa R. |last3=Shah |first3=Priti |title=Living "in the zone": hyperfocus in adult ADHD |journal=ADHD Attention Deficit and Hyperactivity Disorders |date=June 2019 |volume=11 |issue=2 |pages=191–208 |doi=10.1007/s12402-018-0272-y |pmid=30267329}}</ref> or more acutely.<ref name="Glassey_Smilek_2024">{{cite journal |last1=Ayers-Glassey |first1=Samantha |last2=Smilek |first2=Daniel |title=The relations between hyperfocus and similar attentional states, adult ADHD symptoms, and affective dysfunction |journal=Current Psychology |date=March 2024 |volume=43 |issue=12 |pages=11254–11266 |doi=10.1007/s12144-023-05235-3}}</ref> A 2020 study did not find a higher frequency of hyperfocus in adults with ADHD, although it reported a positive correlation with self-reported ADHD traits. The discrepancy with other studies may reflect varying definitions and conceptions of hyperfocus.<ref name="Groen_et_al_2020"/>

A state of hyperfocus has been hypothesised as being beneficial, allowing individuals to focus on tasks for much longer than is typical.<ref name="Ashinoff_Abu_Akel_2019" /> Conversely, it can be difficult to disengage from and shift attention to other stimuli or tasks, leading to excessively prolonged attention.<ref name="Chutko_et_al_2024"/> It is related to risks such as internet addiction (see {{section link||Problematic digital media use}})<ref name="Ishii_et_al_2023" /> and to some types of offending behaviour.<ref>{{Cite journal |vauthors=Worthington R, Wheeler S |date=January 2023 |title=Hyperfocus and offending behaviour: a systematic review |journal=The Journal of Forensic Practice |volume=25 |issue=3 |pages=185–200 |doi=10.1108/JFP-01-2022-0005 |issn=2050-8794 |s2cid=258330884 |url=https://clok.uclan.ac.uk/46646/1/Manuscript%20with%20author%20details%2012.01.21.pdf}}</ref> Recent research has linked hyperfocus to the psychological concepts of [[Flow (psychology)|flow]], an enjoyable experience of deep engagement in an activity, and [[perseveration]], difficulty disengaging or switching from an activity.<ref name="Glassey_Smilek_2024"/>

===IQ test performance===
Certain studies have found that people with ADHD tend to have lower scores on [[intelligence quotient]] (IQ) tests.<ref name="Frazier_2004">{{cite journal |vauthors=Frazier TW, Demaree HA, Youngstrom EA |title=Meta-analysis of intellectual and neuropsychological test performance in attention-deficit/hyperactivity disorder |journal=[[Neuropsychology (journal)|Neuropsychology]] |volume=18 |issue=3 |pages=543–555 |date=July 2004 |pmid=15291732 |doi=10.1037/0894-4105.18.3.543 |s2cid=17628705}}</ref> The significance of this is controversial due to the differences between people with ADHD and the difficulty determining the influence of symptoms, such as distractibility, on lower scores rather than intellectual capacity. In studies of ADHD, higher IQs may be over-represented because many studies exclude individuals who have lower IQs despite those with ADHD scoring on average nine points lower on standardised intelligence measures.<ref name="Mackenzie_2016">{{cite journal |vauthors=Mackenzie GB, Wonders E |title=Rethinking Intelligence Quotient Exclusion Criteria Practices in the Study of Attention Deficit Hyperactivity Disorder |journal=[[Frontiers in Psychology]] |volume=7 |page=794 |date=2016 |pmid=27303350 |pmc=4886698 |doi=10.3389/fpsyg.2016.00794 |doi-access=free}}</ref> However, other studies contradict this, saying that in individuals with high intelligence, there is an increased risk of a missed ADHD diagnosis, possibly because of compensatory strategies in said individuals.<ref>{{cite journal |vauthors=Rommelse N, van der Kruijs M, Damhuis J, Hoek I, Smeets S, Antshel KM, Hoogeveen L, Faraone SV |title=An evidenced-based perspective on the validity of attention-deficit/hyperactivity disorder in the context of high intelligence |journal=[[Neuroscience & Biobehavioral Reviews]] |volume=71 |pages=21–47 |date=December 2016 |pmid=27590827 |doi=10.1016/j.neubiorev.2016.08.032 |hdl-access=free |s2cid=6698847 |hdl=2066/163023}}</ref>

Studies of adults suggest that negative differences in intelligence are not meaningful and may be explained by associated health problems.<ref>{{cite journal |vauthors=Bridgett DJ, Walker ME |title=Intellectual functioning in adults with ADHD: a meta-analytic examination of full scale IQ differences between adults with and without ADHD |journal=Psychological Assessment |volume=18 |issue=1 |pages=1–14 |date=March 2006 |pmid=16594807 |doi=10.1037/1040-3590.18.1.1}}</ref>
[[File:Correlations between mental tests.svg|thumb|Many [[Intelligence quotient|IQ]] tests often use inter-correlation between subtests and the degree of correlation to the "[[G factor (psychometrics)|g-constant]]" and each other as a part of how they measure IQ and test validity. Individuals with ADHD often have disproportionately lower scores in categories relating to [[working memory]] and [[Mental chronometry|processing speed]], which ruins the correlation that those have with IQ and other tasks, necessitating using more resistant sub-tasks like vocabulary tasks in order to get a clear picture on the actual IQ of a patient.]]
When people with ADHD show discrepancies between certain areas of IQ tests compared to others, it is usually irregularities in sub-tests within sections regarding working memory and processing speed. IQ tests rely on what is known as the [[G factor (psychometrics)|g-factor]] as a way to compare different tests to see how predictive they are of the g-constant (general intelligence), as well as the correlation between other sub-tests on a given test and the predictive power of the g-factor. Some with ADHD may have abnormally low scores on sub-tests that invalidate the full-scale IQ score because the correlation between sub-tests is damaged. The [[Wechsler Adult Intelligence Scale|WAIS]] and [[Wechsler Intelligence Scale for Children|WISC]] have attempted to counter this by introducing a substitute scoring system that only counts sub-tests that are robust against executive dysfunction in studies if a discrepancy occurs.<ref name=":0">{{Cite web |last1=Zhu |first1=Jianjun |last2=Raiford |first2=Susan Engi |last3=Coalson |first3=Diane |last4=Saklofske |first4=Donald H. |date=2007 |title=The What, When, and How of the Wechsler General Ability Index |url=https://www.pearsonassessments.com/content/dam/school/global/clinical/us/assets/wechsler/wechsler-gai.pdf |url-status=live |archive-url=https://web.archive.org/web/20250921215234/https://www.pearsonassessments.com/content/dam/school/global/clinical/us/assets/wechsler/wechsler-gai.pdf |archive-date=21 September 2025 |access-date=21 September 2025 |website=Pearson Assessments}}</ref><ref>{{Cite web |last1=Raiford |first1=Susan E. |last2=Weiss |first2=Lawrence G. |last3=Rolfhus |first3=Eric |last4=Coalson |first4=Diane |date=January 2005 |title=Technical Report #4: General Ability Index |url=https://www.pearsonassessments.com/content/dam/school/global/clinical/us/assets/wisc-iv/wisc-iv-technical-report-4.pdf |url-status=live |archive-url=https://web.archive.org/web/20250921220433/https://www.pearsonassessments.com/content/dam/school/global/clinical/us/assets/wisc-iv/wisc-iv-technical-report-4.pdf |archive-date=21 September 2025 |access-date=21 September 2025 |website=Pearson Asessments}}</ref>

On the [[Stanford–Binet Intelligence Scales|Stanford-Binet]], youth with ADHD take longer to complete the test, and have widespread irregularities within sub-tests in working memory domains.<ref>{{Cite journal |last=Runge |first=Meridee |date=2010-03-01 |title=Cognitive Differences Among Individuals with Attention-Deficit/Hyperactivity Disorder on the Stanford-Binet Intelligence Scales, Fifth Edition |url=https://digitalcommons.georgefox.edu/psyd/402 |journal=Doctor of Psychology (PsyD)}}</ref> On the WAIS, the [[Mental calculation|Arithmetic]] and [[Memory span|Digit Span]] task was the most affected in ADHD and other disabilities.<ref>{{Cite journal |last1=Harrison |first1=Allyson G. |last2=Beal |first2=A. Lynne |last3=Armstrong |first3=Irene T. |last4=Gallagher |first4=Anna |date=2024-03-01 |title=Measurement of Working Memory on the Wechsler Adult Intelligence Scale: Should We Subtract Arithmetic? |journal=Psychological Injury and Law |language=en |volume=17 |issue=1 |pages=55–65 |doi=10.1007/s12207-024-09499-3 |issn=1938-9728}}</ref>

As similar deficits and the lack-thereof also exist in individuals with [[Learning disability|learning disabilities]], [[autism]], and other [[Neurodevelopmental disorder|neurodevelopmental disabilities]], discrepancies in sub-tests, even if they satisfy the criteria for successful usage for special scales, such as the one on the WAIS and WISC, cannot alone be used as a definitive way to diagnose an individual with ADHD. Many individuals with NDD's will have similar or even more severe deficits.<ref name=":0" /> ADHD patients with a naturally high IQ will likely not have visible deficits in working memory on standardised tests that are normed on average individuals, and that cognitive heterogeneity in the ADHD population signals that many with ADHD will not have any visible working memory or processing speed deficits visible.<ref>{{Cite journal |last1=Fair |first1=Damien A. |last2=Bathula |first2=Deepti |last3=Nikolas |first3=Molly A. |last4=Nigg |first4=Joel T. |date=2012-04-24 |title=Distinct neuropsychological subgroups in typically developing youth inform heterogeneity in children with ADHD |journal=Proceedings of the National Academy of Sciences |volume=109 |issue=17 |pages=6769–6774 |doi=10.1073/pnas.1115365109 |doi-access=free |pmc=3340031 |pmid=22474392 |bibcode=2012PNAS..109.6769F }}</ref><ref>{{Cite journal |last1=Cadenas |first1=María |last2=Hartman |first2=Catharina |last3=Faraone |first3=Stephen |last4=Antshel |first4=Kevin |last5=Borges |first5=África |last6=Hoogeveen |first6=Lianne |last7=Rommelse |first7=Nanda |date=2020-02-10 |title=Cognitive correlates of attention-deficit hyperactivity disorder in children and adolescents with high intellectual ability |journal=Journal of Neurodevelopmental Disorders |volume=12 |issue=1 |page=6 |doi=10.1186/s11689-020-9307-8 |doi-access=free |issn=1866-1955 |pmc=7008522 |pmid=32039694}}</ref>
==Causes==
ADHD arises from brain maldevelopment especially in the prefrontal executive networks that can arise either from genetic factors (different gene variants and mutations for building and regulating such networks) or from acquired disruptions to the development of these networks and regions involved in [[executive functioning]] and self-regulation.<ref name="Faraone_2021" /><ref name="Antshel_2014" /> Their reduced size, functional connectivity, and activation contribute to the pathophysiology of ADHD, as well as imbalances in the noradrenergic and dopaminergic systems that mediate these brain regions.<ref name="Faraone_2021" /><ref name="Biederman_2005">{{cite journal |vauthors=Biederman J |title=Attention-deficit/hyperactivity disorder: a selective overview |journal=[[Biological Psychiatry (journal)|Biological Psychiatry]] |volume=57 |issue=11 |pages=1215–1220 |date=June 2005 |pmid=15949990 |doi=10.1016/j.biopsych.2004.10.020 |s2cid=23671547}}</ref>

Genetic factors play an important role; ADHD has a heritability rate of 70–80%. The remaining 20–30% of variance is mediated by de-novo mutations and non-shared environmental factors that provide for or produce brain injuries; there is no significant contribution of the rearing family and social environment.{{refn|<ref name=hl/><ref name="Faraone_2019"/><ref name="pmid20141238">{{cite journal |vauthors=Nikolas MA, Burt SA |title=Genetic and environmental influences on ADHD symptom dimensions of inattention and hyperactivity: a meta-analysis |journal=[[Journal of Abnormal Psychology]] |volume=119 |issue=1 |pages=1–17 |date=February 2010 |pmid=20141238 |doi=10.1037/a0018010}}</ref><ref>{{cite journal |vauthors=Demontis D, Walters RK, Martin J, Mattheisen M, Als TD, Agerbo E, Baldursson G, Belliveau R, Bybjerg-Grauholm J, Bækvad-Hansen M, Cerrato F, Chambert K, Churchhouse C, Dumont A, Eriksson N, Gandal M, Goldstein JI, Grasby KL, Grove J, Gudmundsson OO, Hansen CS, Hauberg ME, Hollegaard MV, Howrigan DP, Huang H, Maller JB, Martin AR, Martin NG, Moran J, Pallesen J, Palmer DS, Pedersen CB, Pedersen MG, Poterba T, Poulsen JB, Ripke S, Robinson EB, Satterstrom FK, Stefansson H, Stevens C, Turley P, Walters GB, Won H, Wright MJ, Andreassen OA, Asherson P, Burton CL, Boomsma DI, Cormand B, Dalsgaard S, Franke B, Gelernter J, Geschwind D, Hakonarson H, Haavik J, Kranzler HR, Kuntsi J, Langley K, Lesch KP, Middeldorp C, Reif A, Rohde LA, Roussos P, Schachar R, Sklar P, Sonuga-Barke EJ, Sullivan PF, Thapar A, Tung JY, Waldman ID, Medland SE, Stefansson K, Nordentoft M, Hougaard DM, Werge T, Mors O, Mortensen PB, Daly MJ, Faraone SV, Børglum AD, Neale BM |title=Discovery of the first genome-wide significant risk loci for attention deficit/hyperactivity disorder |journal=[[Nature Genetics]] |volume=51 |issue=1 |pages=63–75 |date=January 2019 |pmid=30478444 |pmc=6481311 |doi=10.1038/s41588-018-0269-7 |hdl-access=free |hdl=10023/20827}}</ref><ref name="Intergenerational" /><ref name="Grimm_2020">{{cite journal |vauthors=Grimm O, Kranz TM, Reif A |title=Genetics of ADHD: What Should the Clinician Know? |journal=[[Current Psychiatry Reports]] |volume=22 |issue=4 |article-number=18 |date=February 2020 |pmid=32108282 |pmc=7046577 |doi=10.1007/s11920-020-1141-x}}</ref>}} Very rarely, ADHD can also be the result of abnormalities in the chromosomes.<ref>{{cite journal |vauthors=Cederlöf M, Ohlsson Gotby A, Larsson H, Serlachius E, Boman M, Långström N, Landén M, Lichtenstein P |title=Klinefelter syndrome and risk of psychosis, autism and ADHD |journal=[[Journal of Psychiatric Research]] |volume=48 |issue=1 |pages=128–130 |date=January 2014 |pmid=24139812 |doi=10.1016/j.jpsychires.2013.10.001}}</ref>

=== Genetics ===
{{See also|Missing heritability problem}}

[[Literature review]]s published in ''[[Biological Psychiatry (journal)|Biological Psychiatry]]'' and in ''[[Molecular Psychiatry]]'' have found the average [[heritability]] estimate of ADHD to be from 0.74 to 0.8, based on  [[Family study|family]], [[Twin study|twin studies]], and [[Adoption study|adoption studies]].<ref>{{cite journal |vauthors=Biederman J, Spencer T |title=Attention-deficit/hyperactivity disorder (ADHD) as a noradrenergic disorder |journal=[[Biological Psychiatry (journal)|Biological Psychiatry]] |volume=46 |issue=9 |pages=1234–1242 |date=November 1999 |pmid=10560028 |doi=10.1016/S0006-3223(99)00192-4 |publisher=[[Elsevier]] |s2cid=45497168 |author1-link=Joseph Biederman}}</ref><ref name="Faraone_2019" /> Additionally, [[Evolutionary psychiatry|evolutionary psychiatrist]] [[Randolph M. Nesse]] has argued that the 5:1 [[Sex differences in psychology|male-to-female sex ratio]] in the [[Mental disorders and gender|epidemiology of ADHD]] suggests that ADHD may be the [[Variability hypothesis|end of a continuum where males are overrepresented at the tails]], citing clinical psychologist [[Simon Baron-Cohen]]'s [[Empathising–systemising theory|suggestion]] for the [[Sex differences in autism|sex ratio in the epidemiology of autism]] as an analogue.<ref name="Baron-Cohen 2002">{{cite journal |vauthors=Baron-Cohen S |title=The extreme male brain theory of autism |journal=[[Trends in Cognitive Sciences]] |volume=6 |issue=6 |pages=248–254 |date=June 2002 |pmid=12039606 |doi=10.1016/S1364-6613(02)01904-6 |url=https://www.cell.com/trends/cognitive-sciences/fulltext/S1364-6613(02)01904-6 |access-date=9 July 2020 |publisher=[[Elsevier]] |url-status=live |s2cid=8098723 |archive-url=https://web.archive.org/web/20130703172532/http://www.cell.com/trends/cognitive-sciences/fulltext/S1364-6613(02)01904-6 |archive-date=3 July 2013 |author-link=Simon Baron-Cohen |url-access=subscription}}</ref><ref name="Nesse 2005 p. 918">{{cite book |vauthors=Nesse RM |author1-link=Randolph M. Nesse |veditors=Buss DM |editor-link=David Buss |title=The Handbook of Evolutionary Psychology |chapter=32. Evolutionary Psychology and Mental Health |page=918 |year=2005 |edition=1st |place=[[Hoboken, New Jersey|Hoboken, NJ]] |publisher=[[Wiley (publisher)|Wiley]] |isbn=978-0-471-26403-3}}</ref><ref name="Nesse 2016 p. 1019">{{cite book |vauthors=Nesse RM |author-link1=Randolph M. Nesse |veditors=Buss DM |editor1-link=David Buss |year=2016 |orig-date=2005 |title=The Handbook of Evolutionary Psychology, Volume 2: Integrations |edition=2nd |chapter=43. Evolutionary Psychology and Mental Health |page=1019 |place=[[Hoboken, New Jersey|Hoboken, NJ]] |publisher=[[Wiley (publisher)|Wiley]] |isbn=978-1-118-75580-8}}</ref>

[[Evolution by natural selection|Natural selection]] has been acting against genetic variants for ADHD over at least 45,000 years, complicating the suggestion that ADHD was an adaptive form of neurodiversity in the human evolutionary past.<ref>{{cite journal |vauthors=Esteller-Cucala P, Maceda I, Børglum AD, Demontis D, Faraone SV, Cormand B, Lao O |title=Genomic analysis of the natural history of attention-deficit/hyperactivity disorder using Neanderthal and ancient Homo sapiens samples |journal=[[Scientific Reports]] |volume=10 |issue=1 |article-number=8622 |date=May 2020 |pmid=32451437 |pmc=7248073 |doi=10.1038/s41598-020-65322-4 |bibcode=2020NatSR..10.8622E}}</ref> The disorder may remain at a stable rate by the balance of genetic mutations and removal rate (natural selection) across generations; over thousands of years, these genetic variants become more stable, decreasing disorder prevalence.<ref>{{cite journal |vauthors=Keller MC |title=The evolutionary persistence of genes that increase mental disorders risk. |journal=[[Current Directions in Psychological Science]] |date=December 2008 |volume=17 |issue=6 |pages=395–399 |doi=10.1111/j.1467-8721.2008.00613 |doi-broken-date=1 July 2025}}</ref> During human evolution, executive functions disrupted in ADHD, likely provide the capacity to bind contingencies across time thereby directing behaviour toward future over immediate events so as to maximise social consequences for humans.<ref>{{cite book |vauthors=Barkley RA |date=2004 |chapter=Attention-deficit/hyperactivity disorder and self-regulation: Taking an evolutionary perspective on executive functioning. |veditors=Baumeister RF, Vohs KD |title=Handbook of self-regulation: Research, theory, and applications |pages=301–323 |publisher=[[Guilford Press]] |url=https://psycnet.apa.org/record/2004-00163-014}}</ref>

ADHD has a high [[heritability]] of 74%, meaning that 74% of the presence of ADHD in the population is due to genetic factors. There are multiple gene variants which each slightly increase the likelihood of a person having ADHD; it is [[polygenic disease|polygenic]] and thus arises through the accumulation of many genetic risks each having a very small effect.<ref name="Faraone_2021" /><ref name="Faraone_2019" /> The siblings of children with ADHD are three to four times more likely to develop the disorder than siblings of children without the disorder.<ref>{{cite book |vauthors=Nolen-Hoeksema S |title=Abnormal Psychology |year=2013 |isbn=978-0-07-803538-8 |page=267 |publisher=[[McGraw-Hill Education]] |edition=6th}}</ref>

The association of maternal smoking observed in large population studies disappears after adjusting for family history of ADHD, which indicates that the association between maternal smoking during pregnancy and ADHD is due to familial or genetic factors that increase the risk for the confluence of smoking and ADHD.<ref>{{cite journal |vauthors=Skoglund C, Chen Q, D'Onofrio BM, Lichtenstein P, Larsson H |title=Familial confounding of the association between maternal smoking during pregnancy and ADHD in offspring |journal=[[Journal of Child Psychology and Psychiatry|Journal of Child Psychology and Psychiatry, and Allied Disciplines]] |volume=55 |issue=1 |pages=61–68 |date=January 2014 |pmid=25359172 |pmc=4217138 |doi=10.1111/jcpp.12124}}</ref><ref>{{cite journal |vauthors=Obel C, Zhu JL, Olsen J, Breining S, Li J, Grønborg TK, Gissler M, Rutter M |title=The risk of attention deficit hyperactivity disorder in children exposed to maternal smoking during pregnancy - a re-examination using a sibling design |journal=[[Journal of Child Psychology and Psychiatry|Journal of Child Psychology and Psychiatry, and Allied Disciplines]] |volume=57 |issue=4 |pages=532–537 |date=April 2016 |pmid=26511313 |doi=10.1111/jcpp.12478 |url=https://kclpure.kcl.ac.uk/portal/en/publications/b67579b4-68c2-4010-86c4-0392822d2662}}</ref>

ADHD presents with reduced size, functional connectivity and activation<ref name="Faraone_2021" /> as well as low noradrenergic and dopaminergic functioning<ref name="Biederman_2005" /><ref>{{cite journal |vauthors=Hinshaw SP |title=Attention Deficit Hyperactivity Disorder (ADHD): Controversy, Developmental Mechanisms, and Multiple Levels of Analysis |journal=[[Annual Review of Clinical Psychology]] |volume=14 |issue=1 |pages=291–316 |date=May 2018 |pmid=29220204 |doi=10.1146/annurev-clinpsy-050817-084917}}</ref> in brain regions and networks crucial for executive functioning and self-regulation.<ref name="Faraone_2021" /><ref name="Barkley_2011a" /><ref name="Antshel_2014" /> Typically, a number of genes are involved, many of which directly affect brain functioning and neurotransmission.<ref name="Faraone_2021" /> Those involved with dopamine include [[Dopamine transporter|DAT]], [[DRD4]], [[DRD5]], [[TAAR1]], [[MAOA]], [[Catechol O-methyltransferase|COMT]], and [[Dopamine-beta-hydroxylase|DBH.]]<ref name="Kebir_2011">{{cite journal |vauthors=Kebir O, Joober R |title=Neuropsychological endophenotypes in attention-deficit/hyperactivity disorder: a review of genetic association studies |journal=[[European Archives of Psychiatry and Clinical Neuroscience]] |volume=261 |issue=8 |pages=583–594 |date=December 2011 |pmid=21409419 |doi=10.1007/s00406-011-0207-5 |s2cid=21383749}}</ref><ref name="Berry_2007" /><ref>{{cite journal |vauthors=Sotnikova TD, Caron MG, Gainetdinov RR |title=Trace amine-associated receptors as emerging therapeutic targets |journal=[[Molecular Pharmacology]] |volume=76 |issue=2 |pages=229–235 |date=August 2009 |pmid=19389919 |pmc=2713119 |doi=10.1124/mol.109.055970}}</ref> Other genes associated with ADHD include [[Serotonin transporter|SERT]], [[HTR1B]], [[SNAP25]], [[GRIN2A]], [[ADRA2A]], [[TPH2]], and [[Brain-derived neurotrophic factor|BDNF]].<ref name="Gizer_2009">{{cite journal |vauthors=Gizer IR, Ficks C, Waldman ID |title=Candidate gene studies of ADHD: a meta-analytic review |journal=[[Human Genetics]] |volume=126 |issue=1 |pages=51–90 |date=July 2009 |pmid=19506906 |doi=10.1007/s00439-009-0694-x |s2cid=166017}}</ref> A common variant of a gene called [[latrophilin 3]] is estimated to be responsible for about 9% of cases and when this variant is present, people are particularly responsive to stimulant medication.<ref>{{cite journal |vauthors=Arcos-Burgos M, Muenke M |title=Toward a better understanding of ADHD: LPHN3 gene variants and the susceptibility to develop ADHD |journal=Attention Deficit and Hyperactivity Disorders |volume=2 |issue=3 |pages=139–147 |date=November 2010 |pmid=21432600 |pmc=3280610 |doi=10.1007/s12402-010-0030-2}}</ref> The [[DRD4–7R|7 repeat variant of dopamine receptor D4]] (DRD4–7R) causes increased inhibitory effects induced by [[dopamine]] and is associated with ADHD. The DRD4 receptor is a [[G protein-coupled receptor]] that inhibits [[adenylyl cyclase]]. The DRD4–7R mutation results in a wide range of behavioural [[phenotype]]s, including ADHD symptoms reflecting split attention.<ref>{{cite journal |vauthors=Nikolaidis A, Gray JR |title=ADHD and the DRD4 exon III 7-repeat polymorphism: an international meta-analysis |journal=[[Social Cognitive and Affective Neuroscience]] |volume=5 |issue=2–3 |pages=188–193 |date=June 2010 |pmid=20019071 |pmc=2894686 |doi=10.1093/scan/nsp049}}</ref> The DRD4 gene is both linked to novelty seeking and ADHD. The genes [[glucose-fructose oxidoreductase|GFOD1]] and [[T-cadherin|CDH13]] show strong genetic associations with ADHD. CDH13's association with [[Autism spectrum disorder|Autism Spectrum Disorder]] (ASD), [[schizophrenia]], bipolar disorder, and [[Depression (mood)|depression]] make it an interesting candidate causative gene.<ref name="Grimm_2020" /> Another candidate causative gene that has been identified is [[Latrophilin 3|ADGRL3]]. In [[zebrafish]], knockout of this gene causes a loss of dopaminergic function in the ventral [[diencephalon]] and the fish display a hyperactive/impulsive [[phenotype]].<ref name="Grimm_2020" />

For [[genetic variation]] to be used as a tool for diagnosis, more validating studies need to be performed. However, smaller studies have shown that [[genetic polymorphism]]s in genes related to [[catecholaminergic]] neurotransmission or the [[SNARE (protein)|SNARE]] complex of the [[synapse]] can reliably predict a person's response to [[Stimulant|stimulant medication]].<ref name="Grimm_2020" /> Rare genetic variants show more relevant clinical significance as their penetrance (the chance of developing the disorder) tends to be much higher.<ref name="Zayats_2020">{{cite journal |vauthors=Zayats T, Neale BM |title=Recent advances in understanding of attention deficit hyperactivity disorder (ADHD): how genetics are shaping our conceptualization of this disorder |journal=F1000Research |volume=8 |page=2060 |date=12 February 2020 |pmid=31824658 |pmc=6896240 |doi=10.12688/f1000research.18959.2 |doi-access=free}}</ref> However their usefulness as tools for diagnosis is limited as no single gene predicts ADHD. ASD shows genetic overlap with ADHD at both common and rare levels of genetic variation.<ref name="Zayats_2020" />

[[Evolutionary psychology|Evolutionary]] [[Evolutionary psychiatry|theorists]] view ADHD traits (such as novelty-seeking, rapid task-switching, and high exploratory drive) as possible cognitive specialisations that were advantageous in ancestral forager-gatherer environments. In modern structured settings these traits may become mismatched, leading to functional impairment. A recent evolutionary-mismatch hypothesis proposes that high trait curiosity associated with ADHD prepared ancestors to discover new opportunities in unpredictable environments, but in information-saturated, stable modern settings this drive may manifest as distractibility or impulsivity.<ref>{{cite journal |last1=Le Cunff |first1=Anne-Laure |year=2024 |title=Distractibility and impulsivity in ADHD as an evolutionary mismatch of high trait curiosity |journal=Evolutionary Psychological Science |volume=10 |issue=3 |pages=282–297 |doi=10.1007/s40806-024-00400-8}}</ref>

=== Environment ===

In addition to genetics, some environmental factors might play a role in causing ADHD.<ref name="Sonu_2013" /><ref name="cdc2016">{{cite web |author=CDC |title=Attention-Deficit / Hyperactivity Disorder (ADHD) |publisher=Centers for Disease Control and Prevention |url=https://www.cdc.gov/ncbddd/adhd/research.html |date=16 March 2016 |access-date=17 April 2016 |url-status=live |archive-date=14 April 2016 |archive-url=https://web.archive.org/web/20160414160548/http://www.cdc.gov/ncbddd/adhd/research.html}}</ref> Alcohol intake during pregnancy can cause [[fetal alcohol spectrum disorder]]s which can include ADHD-like symptoms.<ref name="Burger_2011">{{cite journal |vauthors=Burger PH, Goecke TW, Fasching PA, Moll G, Heinrich H, Beckmann MW, Kornhuber J |title=[How does maternal alcohol consumption during pregnancy affect the development of attention deficit/hyperactivity syndrome in the child] |language=de |journal=Fortschritte der Neurologie-Psychiatrie |volume=79 |issue=9 |pages=500–506 |date=September 2011 |pmid=21739408 |doi=10.1055/s-0031-1273360 |trans-title=How does maternal alcohol consumption during pregnancy affect the development of attention deficit/hyperactivity syndrome in the child |type=Review |s2cid=140766296}}</ref> Children exposed to certain toxic substances, such as [[lead poisoning|lead]] or [[polychlorinated biphenyls]], may develop problems which resemble ADHD.<ref name="nimh" /><ref name="Eubig_2010">{{cite journal |vauthors=Eubig PA, Aguiar A, Schantz SL |title=Lead and PCBs as risk factors for attention deficit/hyperactivity disorder |journal=[[Environmental Health Perspectives]] |volume=118 |issue=12 |pages=1654–1667 |date=December 2010 |pmid=20829149 |pmc=3002184 |doi=10.1289/ehp.0901852 |bibcode=2010EnvHP.118.1654E |type=Review. Research Support, N.I.H., Extramural. Research Support, U.S. Gov't, Non-P.H.S.}}</ref> Perinatal exposure to the [[organophosphate]] [[insecticide]]s [[chlorpyrifos]] and [[Alkyl phosphate|dialkyl phosphate]] is associated with an increased risk; however, the evidence is not conclusive.<ref name="de_Cock_2012">{{cite journal |vauthors=de Cock M, Maas YG, van de Bor M |title=Does perinatal exposure to endocrine disruptors induce autism spectrum and attention deficit hyperactivity disorders? Review |journal=[[Acta Paediatrica]] |volume=101 |issue=8 |pages=811–818 |date=August 2012 |pmid=22458970 |doi=10.1111/j.1651-2227.2012.02693.x |type=Review. Research Support, Non-U.S. Gov't |s2cid=41748237}}</ref> Exposure to tobacco smoke during pregnancy can cause problems with central nervous system development and can increase the risk of ADHD.<ref name="nimh">{{cite web |title=Attention Deficit Hyperactivity Disorder (Easy-to-Read) |url=https://www.nimh.nih.gov/health/publications/attention-deficit-hyperactivity-disorder-what-you-need-to-know |publisher=National Institute of Mental Health |year=2013 |access-date=17 April 2016 |url-status=live |archive-date=14 April 2016 |archive-url=https://web.archive.org/web/20160414031036/http://www.nimh.nih.gov/health/publications/attention-deficit-hyperactivity-disorder-easy-to-read/index.shtml}}</ref><ref name="Abbott_2012">{{cite journal |vauthors=Abbott LC, Winzer-Serhan UH |title=Smoking during pregnancy: lessons learned from epidemiological studies and experimental studies using animal models |journal=[[Critical Reviews in Toxicology]] |volume=42 |issue=4 |pages=279–303 |date=April 2012 |pmid=22394313 |doi=10.3109/10408444.2012.658506 |type=Review |s2cid=38886526}}</ref> [[Nicotine]] exposure during pregnancy may be an environmental risk.<ref>{{cite journal |vauthors=Tiesler CM, Heinrich J |title=Prenatal nicotine exposure and child behavioural problems |journal=[[European Child & Adolescent Psychiatry]] |volume=23 |issue=10 |pages=913–929 |date=October 2014 |pmid=25241028 |pmc=4186967 |doi=10.1007/s00787-014-0615-y}}</ref>

Extreme [[premature birth]], very [[low birth weight]], and extreme neglect, abuse, or social deprivation also increase the risk<ref>{{cite journal |vauthors=Botting N, Powls A, Cooke RW, Marlow N |title=Attention deficit hyperactivity disorders and other psychiatric outcomes in very low birthweight children at 12 years |journal=[[Journal of Child Psychology and Psychiatry|Journal of Child Psychology and Psychiatry, and Allied Disciplines]] |volume=38 |issue=8 |pages=931–941 |date=November 1997 |pmid=9413793 |doi=10.1111/j.1469-7610.1997.tb01612.x |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1469-7610.1997.tb01612.x |access-date=22 March 2022 |url-status=live |archive-url=https://web.archive.org/web/20220517212252/https://onlinelibrary.wiley.com/doi/10.1111/j.1469-7610.1997.tb01612.x |archive-date=17 May 2022 |url-access=subscription}}</ref><ref name="nimh" /><ref name="Thapar-2012">{{cite journal |vauthors=Thapar A, Cooper M, Jefferies R, Stergiakouli E |title=What causes attention deficit hyperactivity disorder? |journal=[[Archives of Disease in Childhood]] |volume=97 |issue=3 |pages=260–265 |date=March 2012 |pmid=21903599 |pmc=3927422 |doi=10.1136/archdischild-2011-300482 |type=Review. Research Support, Non-U.S. Gov't}}</ref> as do certain infections during pregnancy, at birth, and in early childhood. These infections include, among others, various viruses ([[measles]], [[Varicella zoster virus|varicella zoster]] [[encephalitis]], [[rubella]], [[enterovirus 71]]).<ref name="Millichap_2008">{{cite journal |vauthors=Millichap JG |title=Etiologic classification of attention-deficit/hyperactivity disorder |journal=[[Pediatrics (journal)|Pediatrics]] |volume=121 |issue=2 |pages=e358–e365 |date=February 2008 |pmid=18245408 |doi=10.1542/peds.2007-1332 |type=Review |s2cid=24339363}}</ref> At least 30% of children with a [[traumatic brain injury]] later develop ADHD<ref name="Eme-2012">{{cite journal |vauthors=Eme R |date=April 2012 |title=ADHD: an integration with pediatric traumatic brain injury |journal=Expert Review of Neurotherapeutics |volume=12 |issue=4 |pages=475–483 |doi=10.1586/ern.12.15 |pmid=22449218 |s2cid=35718630}}</ref> and about 5% of cases are due to brain damage.<ref name="Erk_2009" />

Some studies suggest that in a small number of children, artificial [[food dye]]s or [[preservatives]] may be associated with an increased prevalence of ADHD or ADHD-like symptoms,<ref name="nimh" /><ref name="pmid22232312">{{cite journal |vauthors=Millichap JG, Yee MM |title=The diet factor in attention-deficit/hyperactivity disorder |journal=[[Pediatrics (journal)|Pediatrics]] |volume=129 |issue=2 |pages=330–337 |date=February 2012 |pmid=22232312 |doi=10.1542/peds.2011-2199 |url=http://pediatrics.aappublications.org/content/129/2/330.long |url-status=live |s2cid=14925322 |archive-url=https://web.archive.org/web/20150911071727/http://pediatrics.aappublications.org/content/129/2/330.long |archive-date=11 September 2015 |url-access=subscription}}</ref> but the evidence is weak and may apply to only children with [[food sensitivities]].<ref name="Sonu_2013" /><ref name="pmid22232312" /><ref name="EncycFoodSafety">{{cite encyclopedia |vauthors=Tomaska LD, Brooke-Taylor S |title=Food Additives&nbsp;– General |pages=449–454 |encyclopedia=Encyclopedia of Food Safety |volume=3 |veditors=Motarjemi Y, Moy GG, Todd EC |publisher=Elsevier/Academic Press |location=Amsterdam |edition=1st |date=2014 |isbn=978-0-12-378613-5 |oclc=865335120}}</ref> The [[European Union]] has put in place regulatory measures based on these concerns.<ref name="FDAdyecomm">{{cite web |date=March 2011 |url=https://www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterials/FoodAdvisoryCommittee/UCM248549.pdf |title=Background Document for the Food Advisory Committee: Certified Color Additives in Food and Possible Association with Attention Deficit Hyperactivity Disorder in Children |publisher=U.S. Food and Drug Administration |archive-date=6 November 2015 |archive-url=https://web.archive.org/web/20151106080629/https://www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterials/FoodAdvisoryCommittee/UCM248549.pdf}}</ref> In a minority of children, [[food intolerance|intolerances]] or [[food allergy|allergies]] to certain foods may worsen ADHD symptoms.<ref name="Nigg_2014" />

Individuals with [[hypokalemic sensory overstimulation]] are sometimes diagnosed as having ADHD, raising the possibility that a subtype of ADHD has a cause that can be understood mechanistically and treated in a novel way. The sensory overload is treatable with oral [[potassium gluconate]].<ref>{{Cite journal |last1=Segal |first1=Michael M. |last2=Rogers |first2=Gary F. |last3=Needleman |first3=Howard L. |last4=Chapman |first4=Catherine A. |date=2007–2012 |title=Hypokalemic Sensory Overstimulation |url=https://journals.sagepub.com/doi/10.1177/0883073807307095 |journal=[[Journal of Child Neurology]] |language=en |volume=22 |issue=12 |pages=1408–1410 |doi=10.1177/0883073807307095 |pmid=18174562 |issn=0883-0738 |url-access=subscription}}</ref>

{{Anchor|ADH and Sugar}}<!-- Do not delete this code as it is used to link to this location regarding sugar and ADHD from other articles.-->
Research does not support popular beliefs that ADHD is caused by eating too much refined sugar, watching too much television, bad parenting, poverty or family chaos; however, they might worsen ADHD symptoms in certain people.<ref name="cdc2016facts">{{cite web |title=Facts About ADHD |publisher=Centers for Disease Control and Prevention |url=https://www.cdc.gov/ncbddd/adhd/facts.html |date=6 January 2016 |access-date=20 March 2016 |url-status=live |archive-date=22 March 2016 |archive-url=https://web.archive.org/web/20160322103310/http://www.cdc.gov/ncbddd/adhd/facts.html}}</ref>

Children who enter school earlier and are of a younger age than their classmates are more likely to have educational and behavioral problems than their peers, which can make them more likely to be diagnosed with ADHD.<ref>{{Cite journal |last1=Evans |first1=William N. |last2=Morrill |first2=Melinda S. |last3=Parente |first3=Stephen T. |date=1 September 2010 |title=Measuring inappropriate medical diagnosis and treatment in survey data: The case of ADHD among school-age children |url=https://linkinghub.elsevier.com/retrieve/pii/S0167629610000962 |journal=[[Journal of Health Economics]] |volume=29 |issue=5 |pages=657–673 |doi=10.1016/j.jhealeco.2010.07.005 |pmid=20739076 |issn=0167-6296 |quote=As Elder and Lubotsky (2009) demonstrate, younger children in classes are more likely to have educational and behavioral problems compared to their peers, and therefore, some children who are relatively young compared to their classroom peers are more likely to be diagnosed with ADHD. These results suggest that the comparison sample for diagnosis should not be other children in class but rather, other children of a similar age within a class. |url-access=subscription}}</ref> Behaviours typical of ADHD occur more commonly in children who have experienced violence and emotional abuse.<ref name="NICE 2009">{{cite book |title=Attention Deficit Hyperactivity Disorder: Diagnosis and Management of ADHD in Children, Young People and Adults |author=National Collaborating Centre for Mental Health |series=NICE Clinical Guidelines |volume=72 |publisher=[[British Psychological Society]] |location=Leicester |isbn=978-1-85433-471-8 |date=2009 |url=https://www.ncbi.nlm.nih.gov/books/NBK53652/ |via=NCBI Bookshelf |url-status=live |archive-url=https://web.archive.org/web/20160113133612/http://www.ncbi.nlm.nih.gov/books/NBK53652/ |archive-date=13 January 2016}}</ref>

== Pathophysiology ==
Current models of ADHD suggest that it is associated with functional impairments in some of the brain's [[neurotransmitter systems]], particularly those involving [[dopamine]] and [[norepinephrine]].<ref name="Malenka ADHD neurosci">{{cite book |title=Molecular Neuropharmacology: A Foundation for Clinical Neuroscience |vauthors=Malenka RC, Nestler EJ, Hyman SE |publisher=McGraw-Hill Medical |year=2009 |isbn=978-0-07-148127-4 |veditors=Sydor A, Brown RY |edition=2nd |location=New York |pages=266, 315, 318–323 |chapter=Chapters 10 and 13 |quote=Early results with structural MRI show thinning of the cerebral cortex in ADHD subjects compared with age-matched controls in prefrontal cortex and posterior parietal cortex, areas involved in working memory and attention.}}</ref> The dopamine and norepinephrine pathways that originate in the [[ventral tegmental area]] and [[locus coeruleus]] project to diverse regions of the brain and govern a variety of cognitive processes.<ref name="VTA+LC projection systems">{{cite journal |vauthors=Chandler DJ, Waterhouse BD, Gao WJ |title=New perspectives on catecholaminergic regulation of executive circuits: evidence for independent modulation of prefrontal functions by midbrain dopaminergic and noradrenergic neurons |journal=[[Frontiers in Neural Circuits]] |volume=8 |page=53 |date=May 2014 |pmid=24904299 |pmc=4033238 |doi=10.3389/fncir.2014.00053 |doi-access=free}}</ref><ref name="Malenka pathways" /> The [[dopamine pathway]]s and [[LC-NA system|norepinephrine pathway]]s which project to the [[prefrontal cortex]] and [[striatum]] are directly responsible for modulating [[executive function]] (cognitive control of behaviour), motivation, reward perception, and motor function;<ref name="Malenka ADHD neurosci" /><ref name="Malenka pathways" /> these pathways are known to play a central role in the [[wikt:pathophysiology|pathophysiology]] of ADHD.<ref name="VTA+LC projection systems" /><ref name="Malenka pathways" /><ref name="pmid22169776" /><ref name="pmid22983386" /> Larger models of ADHD with additional pathways have been proposed.<ref name="pmid22169776">{{cite journal |vauthors=Castellanos FX, Proal E |title=Large-scale brain systems in ADHD: beyond the prefrontal-striatal model |journal=Trends in Cognitive Sciences |volume=16 |issue=1 |pages=17–26 |date=January 2012 |pmid=22169776 |pmc=3272832 |doi=10.1016/j.tics.2011.11.007 |quote=Recent conceptualizations of ADHD have taken seriously the distributed nature of neuronal processing. Most of the candidate networks have focused on prefrontal-striatal-cerebellar circuits, although other posterior regions are also being proposed.}}</ref><ref name="pmid22983386">{{cite journal |vauthors=Cortese S, Kelly C, Chabernaud C, Proal E, Di Martino A, Milham MP, Castellanos FX |title=Toward systems neuroscience of ADHD: a meta-analysis of 55 fMRI studies |journal=[[The American Journal of Psychiatry]] |volume=169 |issue=10 |pages=1038–1055 |date=October 2012 |pmid=22983386 |pmc=3879048 |doi=10.1176/appi.ajp.2012.11101521 |lccn=22024537 |oclc=1480183 |eissn=1535-7228}}</ref>

=== Brain structure ===
[[File:Attention deficit hyperactivity disorder - Attention deficit hyperactivity disorder - Reduced brain volume on the left side from ADHD.jpg|thumb|upright=1.3|The left prefrontal cortex, shown here in blue, is often affected in ADHD]]
In children with ADHD, there is a general reduction of volume in certain brain structures, with a proportionally greater decrease in the volume in the left-sided prefrontal cortex.<ref name="Malenka ADHD neurosci" /><ref name="Krain2006">{{cite journal |vauthors=Krain AL, Castellanos FX |title=Brain development and ADHD |journal=[[Clinical Psychology Review]] |volume=26 |issue=4 |pages=433–444 |date=August 2006 |pmid=16480802 |doi=10.1016/j.cpr.2006.01.005}}</ref> The [[posterior parietal cortex]] also shows thinning in individuals with ADHD compared to controls. Other brain structures in the prefrontal-striatal-cerebellar and prefrontal-striatal-thalamic circuits have also been found to differ between people with and without ADHD.<ref name="Malenka ADHD neurosci" /><ref name="pmid22169776" /><ref name="pmid22983386" />

The subcortical volumes of the [[accumbens]], [[amygdala]], [[Caudate nucleus|caudate]], [[hippocampus]], and [[putamen]] appears smaller in individuals with ADHD compared with controls.<ref>{{cite journal |vauthors=Hoogman M, Bralten J, Hibar DP, Mennes M, Zwiers MP, Schweren LS, van Hulzen KJ, Medland SE, Shumskaya E, Jahanshad N, Zeeuw P, Szekely E, Sudre G, Wolfers T, Onnink AM, Dammers JT, Mostert JC, Vives-Gilabert Y, Kohls G, Oberwelland E, Seitz J, Schulte-Rüther M, Ambrosino S, Doyle AE, Høvik MF, Dramsdahl M, Tamm L, van Erp TG, Dale A, Schork A, Conzelmann A, Zierhut K, Baur R, McCarthy H, Yoncheva YN, Cubillo A, Chantiluke K, Mehta MA, Paloyelis Y, Hohmann S, Baumeister S, Bramati I, Mattos P, Tovar-Moll F, Douglas P, Banaschewski T, Brandeis D, Kuntsi J, Asherson P, Rubia K, Kelly C, Martino AD, Milham MP, Castellanos FX, Frodl T, Zentis M, Lesch KP, Reif A, Pauli P, Jernigan TL, Haavik J, Plessen KJ, Lundervold AJ, Hugdahl K, Seidman LJ, Biederman J, Rommelse N, Heslenfeld DJ, Hartman CA, Hoekstra PJ, Oosterlaan J, Polier GV, Konrad K, Vilarroya O, Ramos-Quiroga JA, Soliva JC, Durston S, Buitelaar JK, Faraone SV, Shaw P, Thompson PM, Franke B |title=Subcortical brain volume differences in participants with attention deficit hyperactivity disorder in children and adults: a cross-sectional mega-analysis |journal=[[The Lancet Psychiatry]] |volume=4 |issue=4 |pages=310–319 |date=April 2017 |pmid=28219628 |pmc=5933934 |doi=10.1016/S2215-0366(17)30049-4}}</ref> Structural MRI studies have also revealed differences in white matter, with marked differences in inter-hemispheric asymmetry between ADHD and typically developing youths.<ref>{{cite journal |vauthors=Douglas PK, Gutman B, Anderson A, Larios C, Lawrence KE, Narr K, Sengupta B, Cooray G, Douglas DB, Thompson PM, McGough JJ, Bookheimer SY |title=Hemispheric brain asymmetry differences in youths with attention-deficit/hyperactivity disorder |journal=NeuroImage. Clinical |volume=18 |pages=744–752 |date=February 2018 |pmid=29876263 |pmc=5988460 |doi=10.1016/j.nicl.2018.02.020}}</ref>

[[Functional magnetic resonance imaging|Functional MRI]] (fMRI) studies have revealed a number of differences between ADHD and control brains. Mirroring what is known from structural findings, fMRI studies have shown evidence for a higher connectivity between subcortical and cortical regions, such as between the caudate and prefrontal cortex. The degree of hyperconnectivity between these regions correlated with the severity of inattention or hyperactivity<ref name="Damiani_2021">{{cite journal |vauthors=Damiani S, Tarchi L, Scalabrini A, Marini S, Provenzani U, Rocchetti M, Oliva F, Politi P |title=Beneath the surface: hyper-connectivity between caudate and salience regions in ADHD fMRI at rest |journal=[[European Child & Adolescent Psychiatry]] |volume=30 |issue=4 |pages=619–631 |date=April 2021 |pmid=32385695 |doi=10.1007/s00787-020-01545-0 |hdl-access=free |s2cid=218540328 |hdl=2318/1755224}}</ref> Hemispheric lateralisation processes have also been postulated as being implicated in ADHD, but empiric results showed contrasting evidence on the topic.<ref name="Tarchi_2022">{{cite journal |vauthors=Tarchi L, Damiani S, Fantoni T, Pisano T, Castellini G, Politi P, Ricca V |title=Centrality and interhemispheric coordination are related to different clinical/behavioral factors in attention deficit/hyperactivity disorder: a resting-state fMRI study |journal=Brain Imaging and Behavior |volume=16 |issue=6 |pages=2526–2542 |date=December 2022 |pmid=35859076 |pmc=9712307 |doi=10.1007/s11682-022-00708-8}}</ref><ref>{{cite journal |vauthors=Mohamed SM, Börger NA, Geuze RH, van der Meere JJ |title=Brain lateralization and self-reported symptoms of ADHD in a population sample of adults: a dimensional approach |journal=[[Frontiers in Psychology]] |volume=6 |page=1418 |date=2015 |pmid=26441789 |pmc=4585266 |doi=10.3389/fpsyg.2015.01418 |doi-access=free}}</ref>

=== Neurotransmitter pathways ===
Previously, it had been suggested that the elevated number of [[dopamine transporter]]s in people with ADHD was part of the pathophysiology, but it appears the elevated numbers may be due to adaptation following exposure to stimulant medication.<ref name="pmid22294258">{{cite journal |vauthors=Fusar-Poli P, Rubia K, Rossi G, Sartori G, Balottin U |title=Striatal dopamine transporter alterations in ADHD: pathophysiology or adaptation to psychostimulants? A meta-analysis |journal=[[The American Journal of Psychiatry]] |volume=169 |issue=3 |pages=264–272 |date=March 2012 |pmid=22294258 |doi=10.1176/appi.ajp.2011.11060940 |lccn=22024537 |hdl=11577/2482784 |doi-access=free |oclc=1480183 |eissn=1535-7228}}</ref> Current models involve the [[mesocorticolimbic projection|mesocorticolimbic dopamine pathway]] and the [[locus coeruleus-noradrenergic system]].<ref name="VTA+LC projection systems" /><ref name="Malenka ADHD neurosci" /><ref name="Malenka pathways" /> ADHD psychostimulants possess treatment efficacy because they increase neurotransmitter activity in these systems.<ref name="Malenka ADHD neurosci" /><ref name="Malenka pathways">{{cite book |vauthors=Malenka RC, Nestler EJ, Hyman SE |veditors=Sydor A, Brown RY |title=Molecular Neuropharmacology: A Foundation for Clinical Neuroscience |year=2009 |publisher=McGraw-Hill Medical |location=New York |isbn=978-0-07-148127-4 |pages=148, 154–157 |edition=2nd |chapter=Chapter 6: Widely Projecting Systems: Monoamines, Acetylcholine, and Orexin |quote={{abbr|DA|dopamine}} has multiple actions in the prefrontal cortex. It promotes the 'cognitive control' of behavior: the selection and successful monitoring of behavior to facilitate attainment of chosen goals. Aspects of cognitive control in which DA plays a role include working memory, the ability to hold information 'on line' in order to guide actions, suppression of prepotent behaviors that compete with goal-directed actions, and control of attention and thus the ability to overcome distractions. Cognitive control is impaired in several disorders, including attention deficit hyperactivity disorder.&nbsp;... Noradrenergic projections from the {{abbr|LC|locus coeruleus}} thus interact with dopaminergic projections from the {{abbr|VTA|ventral tegmental area}} to regulate cognitive control.&nbsp;... it has not been shown that {{abbr|5HT|serotonin}} makes a therapeutic contribution to treatment of ADHD.}}</ref><ref name="cognition enhancers" /> There may additionally be abnormalities in [[Serotonin|serotonergic]], [[glutamate (neurotransmitter)|glutamatergic]], or [[cholinergic]] pathways.<ref name="cognition enhancers" /><ref name="Cortese-2012">{{cite journal |vauthors=Cortese S |title=The neurobiology and genetics of Attention-Deficit/Hyperactivity Disorder (ADHD): what every clinician should know |journal=European Journal of Paediatric Neurology |volume=16 |issue=5 |pages=422–433 |date=September 2012 |pmid=22306277 |doi=10.1016/j.ejpn.2012.01.009}}</ref><ref name="pmid22939004">{{cite journal |vauthors=Lesch KP, Merker S, Reif A, Novak M |title=Dances with black widow spiders: dysregulation of glutamate signalling enters centre stage in ADHD |journal=[[European Neuropsychopharmacology]] |volume=23 |issue=6 |pages=479–491 |date=June 2013 |pmid=22939004 |doi=10.1016/j.euroneuro.2012.07.013 |s2cid=14701654}}</ref>

PET mapping of neocortex receptor distribution indicates that the distribution of μ-opioid receptors is the strongest contributor to cortical abnormalities in ADHD, followed by CB<sub>1</sub> cannabinoid receptors.<ref>{{Cite journal |last1=Hansen |first1=Justine Y. |last2=Shafiei |first2=Golia |last3=Markello |first3=Ross D. |last4=Smart |first4=Kelly |last5=Cox |first5=Sylvia M. L. |last6=Nørgaard |first6=Martin |last7=Beliveau |first7=Vincent |last8=Wu |first8=Yanjun |last9=Gallezot |first9=Jean-Dominique |last10=Aumont |first10=Étienne |last11=Servaes |first11=Stijn |last12=Scala |first12=Stephanie G. |last13=DuBois |first13=Jonathan M. |last14=Wainstein |first14=Gabriel |last15=Bezgin |first15=Gleb |date=2022 |title=Mapping neurotransmitter systems to the structural and functional organization of the human neocortex |journal=[[Nature Neuroscience]] |language=en |volume=25 |issue=11 |pages=1569–1581 |doi=10.1038/s41593-022-01186-3 |pmid=36303070 |pmc=9630096 |issn=1546-1726}}</ref>

=== Executive function and motivation ===
ADHD arises from a core deficit in executive functions (e.g., [[attentional control]], [[inhibitory control]], and [[working memory]]), which are a set of [[Cognition|cognitive processes]] that are required to successfully select and monitor behaviours that facilitate the attainment of one's chosen goals.<ref name="Malenka pathways" /><ref name="Executive functions" /> The executive function impairments that occur in ADHD individuals result in problems with staying organised, time keeping, [[procrastination]] control, maintaining concentration, paying attention, ignoring distractions, regulating emotions, and remembering details.<ref name="Brown_2008" /><ref name="Malenka ADHD neurosci" /><ref name="Malenka pathways" /> People with ADHD appear to have unimpaired long-term memory, and deficits in long-term recall appear to be attributed to impairments in working memory.<ref name="pmid24232170">{{cite journal |vauthors=Skodzik T, Holling H, Pedersen A |title=Long-Term Memory Performance in Adult ADHD |journal=[[Journal of Attention Disorders]] |volume=21 |issue=4 |pages=267–283 |date=February 2017 |pmid=24232170 |doi=10.1177/1087054713510561 |s2cid=27070077}}</ref> Due to the rates of brain maturation and the increasing demands for executive control as a person gets older, ADHD impairments may not fully manifest themselves until adolescence or even early adulthood.<ref name="Brown_2008" /> Conversely, brain maturation trajectories, potentially exhibiting diverging longitudinal trends in ADHD, may support a later improvement in executive functions after reaching adulthood.<ref name="Tarchi_2022" />

ADHD has also been associated with motivational deficits in children. Children with ADHD often find it difficult to focus on long-term over short-term rewards, and exhibit impulsive behaviour for short-term rewards.<ref name="Motivation">{{cite journal |vauthors=Modesto-Lowe V, Chaplin M, Soovajian V, Meyer A |title=Are motivation deficits underestimated in patients with ADHD? A review of the literature |journal=Postgraduate Medicine |volume=125 |issue=4 |pages=47–52 |date=July 2013 |pmid=23933893 |doi=10.3810/pgm.2013.07.2677 |quote=Behavioral studies show altered processing of reinforcement and incentives in children with ADHD. These children respond more impulsively to rewards and choose small, immediate rewards over larger, delayed incentives. Interestingly, a high intensity of reinforcement is effective in improving task performance in children with ADHD. Pharmacotherapy may also improve task persistence in these children.&nbsp;... Previous studies suggest that a clinical approach using interventions to improve motivational processes in patients with ADHD may improve outcomes as children with ADHD transition into adolescence and adulthood. |s2cid=24817804}}</ref>

=== Paradoxical reaction to neuroactive substances ===
Another sign of the structurally altered signal processing in the central nervous system in this group of people is the conspicuously common [[paradoxical reaction]] ({{circa|10–20%}} of patients). These are unexpected reactions in the opposite direction as with a normal effect, or otherwise significant different reactions. These are reactions to neuroactive substances such as [[local anesthetic]] at the dentist, [[sedative]], [[caffeine]], [[antihistamine]], weak [[neuroleptics]] and central and peripheral [[painkillers]]. Since the causes of ''paradoxical reactions'' are at least partly genetic, it may be useful in critical situations, for example before operations, to ask whether such abnormalities may also exist in family members.<ref name="PMID21886668">{{cite journal |pmc=3163785 |date=2011 |title=Paradoxical Reaction in ADHD |journal=Deutsches Ärzteblatt International |department=Correspondence |volume=108 |issue=31–32 |pages=541; author reply 541–2 |doi=10.3238/arztebl.2011.0541a |pmid=21886668 |vauthors=Langguth B, Bär R, Wodarz N, Wittmann M, Laufkötter R |language=de}}</ref><ref>{{cite journal |vauthors=Laufkötter R, Langguth B, Johann M, Eichhammer P, Hajak G |title=ADHS des Erwachsenenalters und Komorbiditäten |language=de |trans-title= |journal=PsychoNeuro |volume=31 |date=2005 |issue=11 |page=563 |doi=10.1055/s-2005-923370 |doi-access=free}}</ref>

==Diagnosis==
<!--Use [[Diagnosis of attention deficit hyperactivity disorder]] not [[Attention deficit hyperactivity disorder#Diagnosis]] to prevent broken anchors just in case the section is renamed -->

ADHD is diagnosed by an assessment of a person's behavioural and mental development, including ruling out the effects of drugs, medications, and other medical or psychiatric problems as explanations for the symptoms.<ref name="NICE2009-part2">{{cite book |author=National Collaborating Centre for Mental Health |url=https://www.ncbi.nlm.nih.gov/books/NBK53652/ |title=Attention Deficit Hyperactivity Disorder: Diagnosis and Management of ADHD in Children, Young People and Adults |date=2009 |publisher=[[British Psychological Society]] |isbn=978-1-85433-471-8 |series=NICE Clinical Guidelines |volume=72 |location=Leicester |pages=[https://www.ncbi.nlm.nih.gov/books/NBK53663/#ch2.s8 18–26], [https://www.ncbi.nlm.nih.gov/books/NBK53663/#ch2.s41 38] |chapter=Attention Deficit Hyperactivity Disorder |chapter-url=https://www.ncbi.nlm.nih.gov/books/NBK53663/ |archive-url=https://web.archive.org/web/20160113133612/http://www.ncbi.nlm.nih.gov/books/NBK53652/ |archive-date=13 January 2016 |url-status=live |via=NCBI Bookshelf}}</ref> Childhood and adolescent ADHD diagnosis often takes into account feedback from parents and teachers<ref name="Lake2011">{{cite book |vauthors=Dulcan MK, Lake MB |url=https://books.google.com/books?id=HvTa2nArhOsC |title=Concise Guide to Child and Adolescent Psychiatry |date=2011 |publisher=American Psychiatric Publishing |isbn=978-1-58562-416-4 |edition=4th illustrated |page=34 |chapter=Axis I Disorders Usually First Diagnosed in Infancy, Childhood or Adolescence: Attention-Deficit and Disruptive Behavior Disorders}}</ref> with most diagnoses begun after a teacher raises concerns.<ref name="Erk_2009">{{cite book |vauthors=Mayes R, Bagwell C, Erkulwater JL |title=Medicating Children: ADHD and Pediatric Mental Health |publisher=[[Harvard University Press]] |date=2009 |pages=4–24 |isbn=978-0-674-03163-0 |edition=illustrated}}</ref> While many tools exist to aid in the diagnosis of ADHD, their validity varies in different populations, and a reliable and valid diagnosis requires confirmation by a clinician while supplemented by standardised rating scales and input from multiple informants across various settings.<ref name="Peterson_2024">{{cite journal |vauthors=Peterson BS, Trampush J, Brown M, Maglione M, Bolshakova M, Rozelle M, Miles J, Pakdaman S, Yagyu S, Motala A, Hempel S |title=Tools for the Diagnosis of ADHD in Children and Adolescents: A Systematic Review |journal=[[Pediatrics (journal)|Pediatrics]] |volume=153 |issue=4 |date=April 2024 |article-number=e2024065854 |pmid=38523599 |doi=10.1542/peds.2024-065854}}</ref> Most diagnosis in children is seen in low-income families, and more in Caucasian children in comparison to Black, Hispanic, and Asian children, however, the diagnosis may be influenced by racial and socio-economic biases.<ref>{{Cite report |url=https://effectivehealthcare.ahrq.gov/products/attention-deficit-hyperactivity-disorder/research |title=ADHD Diagnosis and Treatment in Children and Adolescents |last1=Peterson |first1=Bradley S. |last2=Trampush |first2=Joey |last3=Maglione |first3=Margaret |last4=Bolshakova |first4=Maria |last5=Brown |first5=Morah |last6=Rozelle |first6=Mary |last7=Motala |first7=Aneesa |last8=Yagyu |first8=Sachi |last9=Miles |first9=Jeremy |date=2024-03-25 |publisher=Agency for Healthcare Research and Quality (AHRQ) |doi=10.23970/ahrqepccer267}}</ref>

The diagnosis of ADHD has been criticised as being subjective because it is not based on a biological test. The International Consensus Statement on ADHD concluded that this criticism is unfounded, on the basis that ADHD meets standard criteria for validity of a mental disorder established by Robins and Guze. They attest that the disorder is considered valid because: 1) well-trained professionals in a variety of settings and cultures agree on its presence or absence using well-defined criteria and 2) the diagnosis is useful for predicting a) additional problems the patient may have (e.g., difficulties learning in school); b) future patient outcomes (e.g., risk for future drug abuse); c) response to treatment (e.g., medications and psychological treatments); and d) features that indicate a consistent set of causes for the disorder (e.g., findings from genetics or brain imaging), and that professional associations have endorsed and published guidelines for diagnosing ADHD.<ref name="Faraone_2021" />

The most commonly used rating scales for diagnosing ADHD in children are the [[Achenbach System of Empirically Based Assessment|Achenbach System of Empirically Based Assessment (ASEBA)]] and include the [[Child Behavior Checklist|Child Behavior Checklist (CBCL)]] used for parents to rate their child's behaviour, the Youth Self Report Form (YSR) used for children to rate their own behaviour, and the Teacher Report Form (TRF) used for teachers to rate their pupil's behaviour. Additional rating scales that have been used alone or in combination with other measures to diagnose ADHD include the Behavior Assessment System for Children (BASC), Behavior Rating Inventory of Executive Function - Second Edition (BRIEF2), [[Conners Comprehensive Behaviour Rating Scale|Revised Conners Rating Scale (CRS-R)]], Conduct-Hyperactive-Attention Problem-Oppositional Symptom scale (CHAOS), Developmental Behavior Checklist Hyperactivity Index (DBC-HI), [[Disruptive Behavior Disorders Rating Scale|Parent Disruptive Behavior Disorder Ratings Scale (DBDRS)]], Diagnostic Infant and Preschool Assessment (DIPA-L), Pediatric Symptom Checklist (PSC), Social Communication Questionnaire (SCQ), Social Responsiveness Scale (SRS), Strengths and Weaknesses of ADHD Symptoms and Normal Behavior Rating Scale (SWAN) and the [[Vanderbilt ADHD diagnostic rating scale]].<ref name="Peterson_2024a">{{Cite journal |title=ADHD Diagnosis and Treatment in Children and Adolescents |url=https://effectivehealthcare.ahrq.gov/products/attention-deficit-hyperactivity-disorder/research |access-date=22 June 2024 |website=effectivehealthcare.ahrq.gov |date=2024 |language=en |doi=10.23970/ahrqepccer267 |pmid=38657097 |vauthors=Peterson BS, Trampush J, Maglione M, Bolshakova M, Brown M, Rozelle M, Motala A, Yagyu S, Miles J, Pakdaman S, Gastelum M, Nguyen BT, Tokutomi E, Lee E, Belay JZ, Schaefer C, Coughlin B, Celosse K, Molakalapalli S, Shaw B, Sazmin T, Onyekwuluje AN, Tolentino D, Hempel S |url-access=subscription}}</ref>

The ASEBA, BASC, CHAOS, CRS, and Vanderbilt diagnostic rating scales allow for both parents and teachers as raters in the diagnosis of childhood and adolescent ADHD. Adolescents may also self report their symptoms using self report scales from the ASEBA, SWAN, and the Dominic Interactive for Adolescents-Revised (DIA-R).<ref name="Peterson_2024a" /> Self-rating scales, such as the [[ADHD rating scale]] and the [[Vanderbilt ADHD diagnostic rating scale]], are used in the screening and evaluation of ADHD.<ref name="Smith(2007) in Mash & Barkley EBA">{{Cite book |title=Assessment of Childhood Disorders |vauthors=Smith BJ, Barkley RA, Shapiro CJ |publisher=[[Guilford Press]] |year=2007 |isbn=978-1-59385-493-5 |veditors=Mash EJ, Barkley RA |edition=4th |location=New York, NY |pages=53–131 |chapter=Attention-Deficit/Hyperactivity Disorder}}</ref>

Based on a 2024 systematic literature review and meta analysis commissioned by the Patient-Centered Outcomes Research Institute (PCORI), rating scales based on parent report, teacher report, or self-assessment from the adolescent have high internal consistency as a diagnostic tool meaning that the items within the scale are highly interrelated. The reliability of the scales between raters (i.e. their degree of agreement) however is poor to moderate making it important to include information from multiple raters to best inform a diagnosis.<ref name="Peterson_2024a" />

Imaging studies of the brain do not give consistent results between individuals; thus, they are only used for research purposes and not a diagnosis.<ref>{{cite web |url=http://www.merckmedicus.com/pp/us/hcp/diseasemodules/adhd/pathophysiology.jsp |work = MerckMedicus Modules |publisher=Merck & Co., Inc. |location=Whitehouse Station, NJ, USA |title=ADHD&nbsp;–Pathophysiology |archive-url=https://web.archive.org/web/20100501074844/http://www.merckmedicus.com/pp/us/hcp/diseasemodules/adhd/pathophysiology.jsp |archive-date=1 May 2010 |date=August 2002}}</ref> Electroencephalography is not accurate enough to make an ADHD diagnosis.<ref>{{cite journal |vauthors=Al Rahbi HA, Al-Sabri RM, Chitme HR |title=Interventions by pharmacists in out-patient pharmaceutical care |journal=Saudi Pharmaceutical Journal |volume=22 |issue=2 |pages=101–106 |date=April 2014 |pmid=24648820 |pmc=3950532 |doi=10.1016/j.jsps.2013.04.001}}</ref><ref>{{cite journal |vauthors=Adamou M, Fullen T, Jones SL |title=EEG for Diagnosis of Adult ADHD: A Systematic Review With Narrative Analysis |journal=[[Frontiers in Psychiatry]] |volume=11 |article-number=871 |date=25 August 2020 |pmid=33192633 |pmc=7477352 |doi=10.3389/fpsyt.2020.00871 |doi-access=free}}</ref><ref>{{cite journal |vauthors=Lenartowicz A, Loo SK |title=Use of EEG to diagnose ADHD |journal=[[Current Psychiatry Reports]] |volume=16 |issue=11 |article-number=498 |date=November 2014 |pmid=25234074 |pmc=4633088 |doi=10.1007/s11920-014-0498-0}}</ref> A 2024 systematic review concluded that the use of [[biomarker]]s such as blood or urine samples, [[Electroencephalography|electroencephalogram]] (EEG) markers, and [[neuroimaging]] such as [[Magnetic resonance imaging|MRIs]], in diagnosis for ADHD remains unclear; studies showed great variability, did not assess test-retest reliability, and were not independently replicable.<ref name="Peterson_2024" />

In North America and Australia, DSM-5 criteria are used for diagnosis, while European countries usually use the ICD-11 criteria. ADHD is alternately classified as [[neurodevelopmental disorder]]<ref name="Caroline2010">{{Cite book |url=https://books.google.com/books?id=PaO3jsaGkeYC&pg=PA133 |title=Encyclopedia of Cross-Cultural School Psychology |publisher=Springer Science & Business Media |year=2010 |isbn=978-0-387-71798-2 |veditors=Caroline SC |page=133 |access-date=1 February 2016 |archive-date=22 December 2020 |archive-url=https://web.archive.org/web/20201222193428/https://books.google.com/books?id=PaO3jsaGkeYC&pg=PA133 |url-status=live}}</ref> or a [[Disruptive behavior disorder|disruptive behaviour disorder]] along with [[Oppositional defiant disorder|ODD]], [[Conduct disorder|CD]], and [[antisocial personality disorder]].<ref name="google-book-ref">{{Cite book |vauthors=Wiener JM, Dulcan MK |title=Textbook Of Child and Adolescent Psychiatry |publisher=American Psychiatric Publishing |edition=illustrated |year=2004 |isbn=978-1-58562-057-9 |url=https://books.google.com/books?id=EIgGKcp0SpkC |access-date=2 November 2014 |url-status=live |archive-url=https://web.archive.org/web/20160506182138/https://books.google.com/books?id=EIgGKcp0SpkC |archive-date=6 May 2016}}</ref> A diagnosis does not imply a [[neurological disorder]].<ref name="NICE 2009" />

Very few studies have been conducted on diagnosis of ADHD on children younger than 7 years of age, and those that have were found in a 2024 systematic review to be of low or insufficient strength of evidence.<ref name="Peterson_2024a" /> A 2024 systematic review commissioned by the Patient-Centered Outcomes Research Institute (PCORI) highlighted that although a variety of diagnostic approaches show potential, there is substantial variability in their performance across studies. The same review found that many studies did not include information on the impact associated with a misdiagnosis or the downsides of administering diagnostic assessments. <ref>{{Cite journal |url=https://effectivehealthcare.ahrq.gov/products/attention-deficit-hyperactivity-disorder/research |access-date=2025-10-27 |website=effectivehealthcare.ahrq.gov |date=2024 |doi=10.23970/ahrqepccer267| vauthors = Peterson BS, Trampush J, Maglione M, Bolshakova M, Brown M, Rozelle M, Motala A, Yagyu S, Miles J, Pakdaman S, Gastelum M, Nguyen BT, Tokutomi E, Lee E, Belay JZ, Schaefer C, Coughlin B, Celosse K, Molakalapalli S, Shaw B, Sazmin T, Onyekwuluje AN, Tolentino D, Hempel S |pmid=38657097 }}</ref>  The CBCL and Disruptive Behavior Diagnostic Observation Schedule (DB-DOS) showed good performance, while BRIEF worked very well. However, there is not enough studies on children younger than 7 years of age to determine which diagnosis method is the most effective.<ref>{{Cite report |url=https://effectivehealthcare.ahrq.gov/products/attention-deficit-hyperactivity-disorder/research |title=ADHD Diagnosis and Treatment in Children and Adolescents |last1=Peterson |first1=Bradley S. |last2=Trampush |first2=Joey |last3=Maglione |first3=Margaret |last4=Bolshakova |first4=Maria |last5=Brown |first5=Morah |last6=Rozelle |first6=Mary |last7=Motala |first7=Aneesa |last8=Yagyu |first8=Sachi |last9=Miles |first9=Jeremy |date=25 March 2024 |publisher=Agency for Healthcare Research and Quality (AHRQ) |doi=10.23970/ahrqepccer267 |url-access=subscription}}</ref> The review emphasized that diagnostic accuracy often depends on the comparison group—whether children with ADHD are being distinguished from typically developing peers or from other clinically referred youth—and that multiple informants (such as parents, teachers, and the youth themselves) may be necessary to improve diagnostic accuracy due to poor-to-moderate agreement between raters.<ref name="Peterson_2024a" />

===Classification===
====Diagnostic and Statistical Manual====
As with many other psychiatric disorders, a formal diagnosis should be made by a qualified professional based on a set number of criteria. In the United States, these criteria are defined by the [[American Psychiatric Association]] in the [[Diagnostic and Statistical Manual of Mental Disorders|DSM]]. Based on the DSM-5 criteria published in 2013 and the DSM-5-TR criteria published in 2022, there are three presentations of ADHD:

# ADHD, predominantly inattentive presentation, presents with symptoms including being easily distracted, forgetful, daydreaming, disorganisation, poor sustained attention, and difficulty completing tasks.
# ADHD, predominantly hyperactive-impulsive presentation, presents with excessive fidgeting and restlessness, hyperactivity, and difficulty waiting and remaining seated.
# ADHD, combined presentation, is a combination of the first two presentations.

This subdivision is based on presence of at least six (in children) or five (in older teenagers and adults)<ref>{{cite web |title=Adult ADHD: Diagnosis |url=https://www.camh.ca/en/professionals/treating-conditions-and-disorders/adult-adhd/adult-adhd---diagnosis |access-date=17 April 2022 |website=CAMH |archive-date=21 June 2021 |archive-url=https://web.archive.org/web/20210621130901/https://www.camh.ca/en/professionals/treating-conditions-and-disorders/adult-adhd/adult-adhd---diagnosis |url-status=live}}</ref> out of nine long-term (lasting at least six months) symptoms of inattention, hyperactivity–impulsivity, or both.<ref name="DSM5" /><ref name="DSM5TR" /> To be considered, several symptoms must have appeared by the age of six to twelve and occur in more than one environment (e.g. at home and at school or work). The symptoms must be inappropriate for a child of that age<ref name="pmid21991721">{{cite journal |vauthors=Berger I |title=Diagnosis of attention deficit hyperactivity disorder: much ado about something |journal=[[Israel Medical Association Journal]] |volume=13 |issue=9 |pages=571–574 |date=September 2011 |pmid=21991721 |url=https://www.ima.org.il/FilesUpload/IMAJ/0/40/20032.pdf |access-date=23 May 2013 |url-status=live |archive-url=https://web.archive.org/web/20200728130553/https://www.ima.org.il/filesupload/imaj/0/40/20032.pdf |archive-date=28 July 2020}}</ref> and there must be clear evidence that they are causing impairment in multiple domains of life.<ref name="pmid23755024">{{cite journal |vauthors=Steinau S |title=Diagnostic Criteria in Attention Deficit Hyperactivity Disorder - Changes in DSM 5 |journal=[[Frontiers in Psychiatry]] |volume=4 |page=49 |year=2013 |pmid=23755024 |pmc=3667245 |doi=10.3389/fpsyt.2013.00049 |doi-access=free}}</ref>

The DSM-5 and the DSM-5-TR also provide two diagnoses for individuals who have symptoms of ADHD but do not entirely meet the requirements. ''Other Specified ADHD'' allows the clinician to describe why the individual does not meet the criteria, whereas ''Unspecified ADHD'' is used where the clinician chooses not to describe the reason.<ref name="DSM5" /><ref name="DSM5TR" />

====International Classification of Diseases====
In the eleventh revision of the [[International Statistical Classification of Diseases and Related Health Problems]] ([[ICD-11]]) by the [[World Health Organization]], the disorder is classified as Attention deficit hyperactivity disorder (code 6A05). The defined subtypes are ''predominantly inattentive presentation'' (6A05.0); ''predominantly hyperactive-impulsive presentation'' (6A05.1); and ''combined presentation'' (6A05.2). However, the ICD-11 includes two residual categories for individuals who do not entirely match any of the defined subtypes: ''other specified presentation'' (6A05.Y) where the clinician includes detail on the individual's presentation; and ''presentation unspecified'' (6A05.Z) where the clinician does not provide detail.<ref name="ICD-11">{{cite encyclopedia |title=6A05 Attention deficit hyperactivity disorder |date=February 2022<!-- The most recent update as of the access date --> |orig-date=2019<!-- This is when it was adopted by the World Health Assembly --> |url=https://icd.who.int/browse11/l-m/en#/http://id.who.int/icd/entity/821852937 |encyclopedia=International Classification of Diseases |edition=11th |access-date=8 May 2022 |archive-date=1 August 2018 |archive-url=https://archive.today/20180801205234/https://icd.who.int/browse11/l-m/en%23/http://id.who.int/icd/entity/294762853#/http://id.who.int/icd/entity/821852937 |url-status=live}}</ref>

In the tenth revision ([[ICD-10]]), the symptoms of ''hyperkinetic disorder'' were analogous to ADHD in the ICD-11. When a [[conduct disorder]] <!-- a type of disorder, its not CD --> (as defined by ICD-10)<ref name="ICD10">{{cite book |title=International Statistical Classification of Diseases and Related Health Problems 10th Revision |year=2010 |publisher=World Health Organisation |chapter=F90 Hyperkinetic disorders |chapter-url=http://apps.who.int/classifications/icd10/browse/2010/en#/F90 |access-date=2 November 2014 |url-status=live |archive-date=2 November 2014 |archive-url=https://web.archive.org/web/20141102133725/http://apps.who.int/classifications/icd10/browse/2010/en#/F90}}</ref> is present, the condition was referred to as ''hyperkinetic conduct disorder''. Otherwise, the disorder was classified as ''disturbance of activity and attention'', ''other hyperkinetic disorders'' or ''hyperkinetic disorders, unspecified''. The latter was sometimes referred to as ''hyperkinetic syndrome''.<ref name="ICD10" />

====Social construct theory====
The [[social construct theory of ADHD]] suggests that, because the boundaries between normal and abnormal behaviour are socially constructed (i.e. jointly created and validated by all members of society, and in particular by [[physician]]s, parents, teachers, and others), it then follows that subjective valuations and judgements determine which diagnostic criteria are used and thus, the number of people affected.<ref>{{cite journal |vauthors=Parens E, Johnston J |title=Facts, values, and attention-deficit hyperactivity disorder (ADHD): an update on the controversies |journal=Child and Adolescent Psychiatry and Mental Health |volume=3 |issue=1 |article-number=1 |date=January 2009 |pmid=19152690 |pmc=2637252 |doi=10.1186/1753-2000-3-1 |doi-access=free}}</ref> [[Thomas Szasz]], a supporter of this theory, has argued that ADHD was "invented and then given a name".<ref>{{Cite book |author-link=Thomas Szasz |url=https://books.google.com/books?id=29HP1q6JrgYC |title=Pharmacracy: medicine and politics in America |vauthors=Szasz T |publisher=Praeger |year=2001 |isbn=978-0-275-97196-0 |location=Westport, CT |page=101 |chapter=Psychiatric Medicine: Disorder |quote=Mental diseases are ''invented'' and then given a name, for example attention deficit hyperactivity disorder (ADHD).}}</ref>

===Adults===
{{Main|Adult attention deficit hyperactivity disorder}}

Adults with ADHD are diagnosed under the same criteria, including that their signs must have been present by the age of six to twelve. The individual is the best source for information in diagnosis, however others may provide useful information about the individual's symptoms currently and in childhood; a family history of ADHD also adds weight to a diagnosis.<ref name="Kooij_2010" />{{rp|7,9}} Certain assessments, such as the [[Wender Utah Rating Scale]] (WURS), attempt to assess these childhood ADHD symptoms by having adults retrospectively recall their experiences as children.<ref name="pmid38369740">{{cite journal |vauthors=Caroline S SS, Sudhir PM, Mehta UM, Kandasamy A, Thennarasu K, Benegal V |title=Assessing Adult ADHD: An Updated Review of Rating Scales for Adult Attention Deficit Hyperactivity Disorder (ADHD) |journal=[[Journal of Attention Disorders]] |volume=28 |issue=7 |pages=1045–1062 |date=May 2024 |pmid=38369740 |doi=10.1177/10870547241226654}}</ref> While the core symptoms of ADHD are similar in children and adults, they often present differently in adults than in children: for example, excessive physical activity seen in children may present as feelings of restlessness and constant mental activity in adults.<ref name="Kooij_2010" />{{rp|6}}

Worldwide, it is estimated that 2.58% of adults have persistent ADHD (where the individual currently meets the criteria and there is evidence of childhood onset), and 6.76% of adults have symptomatic ADHD (meaning that they currently meet the criteria for ADHD, regardless of childhood onset).<ref name="Song_2021">{{cite journal |vauthors=Song P, Zha M, Yang Q, Zhang Y, Li X, Rudan I |title=The prevalence of adult attention-deficit hyperactivity disorder: A global systematic review and meta-analysis |journal=[[Journal of Global Health]] |volume=11 |article-number=04009 |date=February 2021 |pmid=33692893 |pmc=7916320 |doi=10.7189/jogh.11.04009 |publisher=International Global Health Society |oclc=751737736 |eissn=2047-2986}}</ref> In 2020, this was 139.84 million and 366.33 million affected adults respectively.<ref name="Song_2021" /> Around 15% of children with ADHD continue to meet full DSM-IV-TR criteria at 25 years of age, and 50% still experience some symptoms.<ref name="Kooij_2010" />{{rp|2|quote=In the meta-analysis of these data from Faraone and colleagues it was concluded that about 15% retain the full diagnosis by age 25 years, with a further 50% in partial remission, indicating that around two-thirds of children with ADHD continue to have impairing levels of ADHD symptoms as adults.}} {{As of|2010}}, most adults remain untreated.<ref name="pmid21494335">{{cite journal |vauthors=Culpepper L, Mattingly G |title=Challenges in identifying and managing attention-deficit/hyperactivity disorder in adults in the primary care setting: a review of the literature |journal=Primary Care Companion to the Journal of Clinical Psychiatry |volume=12 |issue=6 |pages=PCC.10r00951 |year=2010 |pmid=21494335 |pmc=3067998 |doi=10.4088/PCC.10r00951pur}}</ref> Many adults with ADHD without diagnosis and treatment have a disorganised life, and some use [[Substance abuse|non-prescribed drugs]] or [[Alcoholism|alcohol]] as a coping mechanism.<ref name="Art.218">{{cite journal |vauthors=Gentile JP, Atiq R, Gillig PM |title=Adult ADHD: Diagnosis, Differential Diagnosis, and Medication Management |journal=Psychiatry |volume=3 |issue=8 |pages=25–30 |date=August 2006 |pmid=20963192 |pmc=2957278 |quote=likelihood that the adult with ADHD has developed coping mechanisms to compensate for his or her impairment}}</ref> Other problems may include relationship and job difficulties, and an increased risk of criminal activities.<ref>{{cite journal |vauthors=Mohr-Jensen C, Steinhausen HC |title=A meta-analysis and systematic review of the risks associated with childhood attention-deficit hyperactivity disorder on long-term outcome of arrests, convictions, and incarcerations |journal=[[Clinical Psychology Review]] |volume=48 |pages=32–42 |date=August 2016 |pmid=27390061 |doi=10.1016/j.cpr.2016.05.002}}</ref><ref name="Kooij_2010" />{{rp|6|quote=Typically, adults with ADHD will not settle after the age of 30 but continue to change and/or lose jobs and relationships, either through boredom or being fired. They are usually underachievers with an estimated annual twenty two days of excess lost role performance. As a consequence relationships and jobs are often short lived. Relationships that last are often impaired due to the inability to listen with concentration to the spouse, not finishing or procrastinating tasks, often being on a 'short fuse' and interrupting conversations. ... Criminality in adulthood is predicted by ADHD and comorbid conduct disorder in childhood, especially with substance abuse and anti-social personality disorder in adulthood. ... ADHD patients are significantly more arrested, convicted, and incarcerated compared to normal controls, and ADHD is increasingly diagnosed in adults in forensic psychiatry.}} Associated mental health problems include depression, anxiety disorders, and learning disabilities.<ref name="Art.218" />

Some ADHD symptoms in adults differ from those seen in children. While children with ADHD may climb and run about excessively, adults may experience an inability to relax, or may talk excessively in social situations.<ref name="Kooij_2010" />{{rp|6}} Adults with ADHD may start relationships impulsively, display sensation-seeking behaviour, and be short-tempered.<ref name="Kooij_2010" />{{rp|6}} Addictive behaviour such as substance abuse and [[gambling]] are common.<ref name="Kooij_2010" />{{rp|6}} Previously, changes in ADHD presentation over time led to those diagnosed as children appearing to have outgrown the DSM-IV criteria.<ref name="Kooij_2010" />{{rp|5–6}} The DSM-5 addresses this issue by differentiating childhood and adult diagnostic criteria, a marked departure from the DSM-IV, which did not fully take into account the differences in impairments seen in adulthood compared to childhood.<ref name="Kooij_2010" />{{rp|5}}

For diagnosis in an adult, the presence of symptoms since childhood is generally required. However, a proportion of adults who meet the criteria for ADHD in adulthood would not have been diagnosed with ADHD as children. Most cases of late-onset ADHD develop the disorder between the ages of 12–16 and may therefore be considered early adult or adolescent-onset ADHD.<ref>{{cite journal |vauthors=Asherson P, Agnew-Blais J |title=Annual Research Review: Does late-onset attention-deficit/hyperactivity disorder exist? |journal=[[Journal of Child Psychology and Psychiatry|Journal of Child Psychology and Psychiatry, and Allied Disciplines]] |volume=60 |issue=4 |pages=333–352 |date=April 2019 |pmid=30843223 |doi=10.1111/jcpp.13020 |doi-access=free}}</ref>

===Differential diagnosis===
{| class="wikitable floatright" style="width:40em; border:solid 1px #999;"
|-
|+ Symptoms related to other disorders<ref name="BBDADHD">{{Cite journal |author1=Consumer Reports |author1-link=Consumer Reports |author2=Drug Effectiveness Review Project |author2-link=Drug Effectiveness Review Project |date=March 2012 |title=Evaluating Prescription Drugs Used to Treat: Attention Deficit Hyperactivity Disorder (ADHD) Comparing Effectiveness, Safety, and Price |journal=Best Buy Drugs |page=2 |url=http://www.consumerreports.org/health/resources/pdf/best-buy-drugs/ADHDFinal.pdf |access-date=12 April 2013 |url-status=live |archive-url=https://web.archive.org/web/20121115014628/http://www.consumerreports.org/health/resources/pdf/best-buy-drugs/ADHDFinal.pdf |archive-date=15 November 2012}}</ref>
|-
! width="35%" |Depressive disorder
! width="30%" |Anxiety disorder
! width="35%" |Bipolar disorder
|-
|
* feelings of hopelessness, [[low self-esteem]], or unhappiness
* loss of interest in hobbies or regular activities
* [[Fatigue (medical)|fatigue]]
* sleep problems
* difficulty maintaining [[attention]]
* change in [[appetite]]
* [[irritability]] or [[hostility]]
* low tolerance for [[Stress (psychological)|stress]]
* thoughts of death
* unexplained pain
|
* persistent feeling of anxiety
* [[irritability]]
* occasional feelings of [[panic]] or [[fear]]
* [[hypervigilance]]
* inability to pay attention
* tire easily
* low tolerance for [[Stress (psychological)|stress]]
* difficulty maintaining attention
|
'''in manic state'''
* excessive [[happiness]]
* hyperactivity
* [[racing thoughts]]
* [[aggression]]
* excessive talking
* [[grandiose delusions]]
* decreased need for sleep
* inappropriate social behaviour
* difficulty maintaining attention
'''in depressive state'''
* same symptoms as in depression section
|}

The DSM provides [[differential diagnosis|differential diagnoses]] – potential alternate explanations for specific symptoms. Assessment and investigation of clinical history determines which is the most appropriate diagnosis. The DSM-5 suggests [[oppositional defiant disorder]], [[intermittent explosive disorder]], and other disorders such as [[stereotypic movement disorder]] and [[Tourette syndrome]], in addition to specific learning disorder, [[intellectual disability]], [[autism]], [[reactive attachment disorder]], [[anxiety disorder]]s, depressive disorders, [[bipolar disorder]], [[disruptive mood dysregulation disorder]], [[substance use disorder]], [[personality disorder]]s, [[psychotic disorders]], medication-induced symptoms, and [[neurocognitive disorders]]. Many but not all of these are also common comorbidities of ADHD.<ref name="DSM5" /> The DSM-5-TR also suggests [[post-traumatic stress disorder]].<ref name="DSM5TR" />

Symptoms of ADHD that particularly relate to disinhibition and [[irritability]] in addition to low-mood and self-esteem as a result of symptom expression might be confusable with [[dysthymia]] and [[bipolar disorder]] as well as with [[borderline personality disorder]], however they are comorbid at a significantly increased rate relative to the general population.<ref name="Kooij_2010" />{{rp|10|Because adults with ADHD often exhibit low self-esteem, low mood, affective lability and irritability, these symptoms may sometimes be confused with dysthymia, cyclothymia or bipolar disorder and with borderline personality disorder.}} Some symptoms that are viewed superficially due to anxiety disorders, intellectual disability or the effects of substance abuse such as intoxication and [[Drug withdrawal|withdrawal]] can overlap to some extent with ADHD symptoms. These disorders can also occur along with ADHD.

Primary sleep disorders may affect attention and behaviour and the symptoms of ADHD may affect sleep.<ref name="Owens2008">{{cite journal |vauthors=Owens JA |title=Sleep disorders and attention-deficit/hyperactivity disorder |journal=[[Current Psychiatry Reports]] |volume=10 |issue=5 |pages=439–444 |date=October 2008 |pmid=18803919 |doi=10.1007/s11920-008-0070-x |s2cid=23624443}}</ref> It is thus recommended that children with ADHD be regularly assessed for sleep problems.<ref>{{cite journal |vauthors=Walters AS, Silvestri R, Zucconi M, Chandrashekariah R, Konofal E |title=Review of the possible relationship and hypothetical links between attention deficit hyperactivity disorder (ADHD) and the simple sleep related movement disorders, parasomnias, hypersomnias, and circadian rhythm disorders |journal=[[Journal of Clinical Sleep Medicine]] |volume=4 |issue=6 |pages=591–600 |date=December 2008 |pmid=19110891 |pmc=2603539 |doi=10.5664/jcsm.27356}}</ref> Sleepiness in children may result in symptoms ranging from the classic ones of yawning and rubbing the eyes, to disinhibition and inattention. [[Obstructive sleep apnea]] can also cause ADHD-like symptoms.<ref name="pmid22670023">{{cite journal |vauthors=Lal C, Strange C, Bachman D |title=Neurocognitive impairment in obstructive sleep apnea |journal=[[Chest (journal)|Chest]] |volume=141 |issue=6 |pages=1601–1610 |date=June 2012 |pmid=22670023 |doi=10.1378/chest.11-2214}}</ref>

In general, the DSM-5-TR can help distinguish between many conditions associated with ADHD-like symptoms by the context in which the symptoms arise.<ref name="DSM5TR" /> For example, children with [[Learning disability|learning disabilities]] may feel distractable and agitated when asked to engage in tasks that require the impaired skill (e.g., reading, math), but not in other situations. A person with an [[intellectual disability]] may develop symptoms that overlap with ADHD when placed in a school environment that is inappropriate for their needs. The type of inattention implicated in ADHD, of poor persistence and sustained attention, differs substantially from selective or oriented inattention seen in [[cognitive disengagement syndrome]] (CDS), as well as from rumination, reexperiencing or mind blanking seen in anxiety disorders or PTSD.

In mood disorders, ADHD-like symptoms may be limited to [[Mania|manic]] or depressive states of an episodic nature. Symptoms overlapping with ADHD in [[psychotic disorders]] may be limited to psychotic states. [[Substance use disorder]], some medications, and certain medical conditions may cause symptoms to appear later in life, while ADHD, as a [[neurodevelopmental disorder]], requires for them to have been present since childhood.

A careful understanding of the symptoms may help establish the difference between ADHD and other disorders.<ref name="DSM5TR" /> For example, the forgetfulness and impulsivity typical of ADHD (e.g., in completing school assignments or following directions) may be distinguished from [[Oppositional defiant disorder|opposition]] when there is no hostility or defiance, although ADHD and ODD are highly comorbid.<ref>{{cite journal | title=Risk factors for comorbid oppositional defiant disorder in attention-deficit/Hyperactivity disorder | journal=European Child & Adolescent Psychiatry | date=2017 | volume=26 | issue=10 | pages=1155–1164 | doi=10.1007/s00787-017-0972-4 | pmid=28283834 | pmc=5610221 | vauthors = Noordermeer SD, Luman M, Weeda WD, Buitelaar JK, Richards JS, Hartman CA, Hoekstra PJ, Franke B, Heslenfeld DJ, Oosterlaan J }}</ref> Tantrums may differ from the outbursts in [[intermittent explosive disorder]] if there is no aggression involved. The fidgetiness observed in ADHD may be differentiated from [[tic]]s or [[Stereotypy|stereotypies]] common in Tourette syndrome or autism.<ref>{{cite journal | title=The relationship between tics, OC, ADHD and autism symptoms: A cross-disorder symptom analysis in Gilles de la Tourette syndrome patients and their family members | journal=Psychiatry Research | date=2016 | volume=237 | pages=138–146 | doi=10.1016/j.psychres.2016.01.051 | pmid=26826899 | pmc=5137472 | vauthors = Huisman-Van Dijk HM, Van De Schoot R, Rijkeboer MM, Mathews CA, Cath DC }}</ref>

Also, the social difficulties often experienced by individuals with ADHD due to inattention (e.g., being unfocused during the interaction and therefore missing cues or being unaware of one's behavior){{sfn|Barkley|Benton|2022|pp=74-76}} or impulsivity (blurting things out, asking intrusive questions, interrupting) may be contrasted with the social detachment and deficits in understanding social cues associated with Autism Spectrum Disorder. Individuals with ADHD may also present signs of the social impairment or emotional and cognitive dysregulation seen in [[personality disorder]]s, but not necessarily such features as [[Borderline personality disorder|a fear of abandonment, an unstable sense of self]], [[Narcissistic personality disorder|narcissistic tendencies]], [[Antisocial personality disorder|aggressiveness]], or other personality features.<ref name="DSM5TR" />

While it is possible and common for many of these different conditions to be comorbid with ADHD, the symptoms must not be better explained by them, as per diagnostic criterion E in the DSM-5.<ref name="DSM5" /><ref name="DSM5TR" /> The symptoms must arise early in life, appear across multiple environments, and cause significant impairment. Moreover, when some of these conditions are in fact comorbid with ADHD, it is still important to distinguish them, as each may need to be treated separately.{{sfn|Barkley|Benton|2022|loc=Other Mental and Emotional Problems}}

==Comorbidities==

===Psychiatric comorbidities===
In children, ADHD occurs with other disorders about two-thirds of the time.<ref name="Walitza_2012" />

Other neurodevelopmental conditions are common comorbidities. [[Autism spectrum disorder]] (ASD), co-occurring at a rate of 21% in those with ADHD, affects social skills, ability to communicate, behaviour, and interests.<ref name="Young_2020">{{cite journal |vauthors=Young S, Hollingdale J, Absoud M, Bolton P, Branney P, Colley W, Craze E, Dave M, Deeley Q, Farrag E, Gudjonsson G, Hill P, Liang HL, Murphy C, Mackintosh P, Murin M, O'Regan F, Ougrin D, Rios P, Stover N, Taylor E, Woodhouse E |date=May 2020 |title=Guidance for identification and treatment of individuals with attention deficit/hyperactivity disorder and autism spectrum disorder based upon expert consensus |journal=[[BMC Medicine]] |publisher=Springer Science and Business Media LLC |volume=18 |issue=1 |article-number=146 |doi=10.1186/s12916-020-01585-y |pmc=7247165 |pmid=32448170 |doi-access=free}}</ref><ref name="NHS2018">{{cite web |date=20 October 2017 |title=Attention deficit hyperactivity disorder (ADHD): Symptoms |url=https://www.nhs.uk/conditions/attention-deficit-hyperactivity-disorder-adhd/symptoms/#related-conditions-in-children-and-teenagers |archive-url=https://web.archive.org/web/20180516015304/https://www.nhs.uk/conditions/attention-deficit-hyperactivity-disorder-adhd/symptoms/#related-conditions-in-children-and-teenagers |archive-date=16 May 2018 |access-date=15 May 2018 |website=[[NHS]]}}</ref> [[Learning disabilities]] have been found to occur in about&nbsp;20–30% of children with ADHD. Learning disabilities can include developmental speech and language disorders, and academic skills disorders.<ref name="BaileyHC">{{cite web |vauthors=Bailey E |date=5 September 2007 |title=ADHD and Learning Disabilities: How can you help your child cope with ADHD and subsequent Learning Difficulties? There is a way. |url=http://www.healthcentral.com/adhd/education-159625-5.html |url-status=live |archive-url=https://web.archive.org/web/20131203092339/http://www.healthcentral.com/adhd/education-159625-5.html |archive-date=3 December 2013 |access-date=15 November 2013 |publisher=Remedy Health Media, LLC.}}</ref> ADHD, however, is not considered a learning disability, but it very frequently causes academic difficulties.<ref name="BaileyHC" /> [[Intellectual disability|Intellectual disabilities]]<ref name="DSM5TR" />{{Rp|page=75|quote=Individuals with ADHD and those with ASD}} and [[Tourette syndrome]]<ref name="NHS2018" /> are also common.

ADHD is often comorbid with disruptive, impulse control, and conduct disorders. [[Oppositional defiant disorder]] (ODD) occurs in about 25% of children with an inattentive presentation and 50% of those with a combined presentation.<ref name="DSM5TR" />{{Rp|page=75|quote=Oppositional defiant disorder co-occurs with ADHD in approximately half of children with the combined presentation and about a quarter with the predominantly inattentive presentation.}} It is characterised by angry or irritable mood, argumentative or defiant behaviour and vindictiveness which are age-inappropriate. [[Conduct disorder]] (CD) is another common comorbid disorder of adolescents with ADHD, and occurs in 25% of individuals with combined presentation.<ref name="DSM5TR" />{{Rp|page=75|quote=Conduct disorder co-occurs in about a quarter of children or adolescents with the combined presentation}} It is characterised by aggression, destruction of property, deceitfulness, theft and violations of rules.<ref name="UTP2008">{{cite web |vauthors=Krull KR |date=5 December 2007 |title=Evaluation and diagnosis of attention deficit hyperactivity disorder in children |url=https://www.uptodate.com/contents/attention-deficit-hyperactivity-disorder-in-children-and-adolescents-clinical-features-and-diagnosis |url-access=subscription |url-status=live |archive-url=https://web.archive.org/web/20090605040744/http://www.uptodate.com/online/content/topic.do?topicKey=behavior%2F8293#5 |archive-date=5 June 2009 |access-date=12 September 2008 |work=Uptodate |publisher=Wolters Kluwer Health}}</ref> Adolescents with ADHD who also have CD are more likely to develop [[antisocial personality disorder]] in adulthood.<ref name="pmid19428109">{{cite journal |vauthors=Hofvander B, Ossowski D, Lundström S, Anckarsäter H |year=2009 |title=Continuity of aggressive antisocial behavior from childhood to adulthood: The question of phenotype definition |url=https://lup.lub.lu.se/record/1412513 |url-status=live |journal=International Journal of Law and Psychiatry |volume=32 |issue=4 |pages=224–234 |doi=10.1016/j.ijlp.2009.04.004 |pmid=19428109 |archive-url=https://web.archive.org/web/20220517212251/https://lup.lub.lu.se/search/publication/1412513 |archive-date=17 May 2022 |access-date=22 November 2021}}</ref> Brain imaging supports that CD and ADHD are separate conditions: conduct disorder was shown to reduce the size of one's [[Temporal lobe|temporal]] lobe and [[limbic system]], and increase the size of one's [[orbitofrontal cortex]], whereas ADHD was shown to reduce connections in the [[cerebellum]] and [[prefrontal cortex]] more broadly. Conduct disorder involves more impairment in motivation control than ADHD.<ref name="pmid21094938">{{cite journal |vauthors=Rubia K |date=June 2011 |title="Cool" inferior frontostriatal dysfunction in attention-deficit/hyperactivity disorder versus "hot" ventromedial orbitofrontal-limbic dysfunction in conduct disorder: a review |journal=[[Biological Psychiatry (journal)|Biological Psychiatry]] |publisher=Elsevier BV/The Society of Biological Psychiatry |volume=69 |issue=12 |pages=e69–e87 |doi=10.1016/j.biopsych.2010.09.023 |pmid=21094938 |s2cid=14987165}}</ref> [[Intermittent explosive disorder]] is characterised by sudden and disproportionate outbursts of anger and co-occurs in individuals with ADHD more frequently than in the general population.<ref>{{Cite journal |last1=Radwan |first1=Karam |last2=Coccaro |first2=Emil F. |date=28 May 2020 |title=Comorbidity of disruptive behavior disorders and intermittent explosive disorder |journal=Child and Adolescent Psychiatry and Mental Health |volume=14 |issue=1 |page=24 |doi=10.1186/s13034-020-00330-w |issn=1753-2000 |pmc=7257202 |pmid=32514306 |doi-access=free}}</ref>

[[Borderline personality disorder]] has also been noted to co-occur with ADHD,<ref name="PM">{{cite journal |vauthors=Ferrer M, Andión O, Matalí J, Valero S, Navarro JA, Ramos-Quiroga JA, Torrubia R, Casas M |date=December 2010 |title=Comorbid attention-deficit/hyperactivity disorder in borderline patients defines an impulsive subtype of borderline personality disorder |journal=[[Journal of Personality Disorders]] |volume=24 |issue=6 |pages=812–822 |doi=10.1521/pedi.2010.24.6.812 |pmid=21158602}}{{primary source inline|date=May 2013}}</ref> though more recent research suggests this may be due to historical biases leading to misdiagnoses.<ref>{{bulleted list||{{cite journal |vauthors=Kuja-Halkola R, Lind Juto K, Skoglund C, Rück C, Mataix-Cols D, Pérez-Vigil A, Larsson J, Hellner C, Långström N, Petrovic P, Lichtenstein P, Larsson H |title=Do borderline personality disorder and attention-deficit/hyperactivity disorder co-aggregate in families? A population-based study of 2 million Swedes |journal=[[Molecular Psychiatry]] |date=January 2021 |volume=26 |number=1 |pages=341–349 |doi=10.1038/s41380-018-0248-5 |pmid=30323291 |pmc=7815504}}|{{cite magazine |vauthors=Littman K |date=February 2021 |title=When Women Battle ADHD and Borderline Personality Disorder |magazine=[[Additude Magazine]] |url=https://www.additudemag.com/adhd-and-bpd-women-borderline-personality-disorder/}}|{{cite journal |vauthors=Ditrich I, Philipsen A, Matthies S |title=Borderline personality disorder (BPD) and attention deficit hyperactivity disorder (ADHD) revisited – a review-update on common grounds and subtle distinctions |journal=Borderline Personality Disorder and Emotion Dysregulation |volume=8 |number=22 |date=2021 |article-number=22 |doi=10.1186/s40479-021-00162-w |doi-access=free |pmid=34229766 |pmc=8261991 |issn=2051-6673}}|{{cite journal |vauthors=Asherson P, Young AH, Eich-Höchli D, Moran P, Porsdal V, Deberdt W |date=2014 |title=Differential diagnosis, comorbidity, and treatment of attention-deficit/hyperactivity disorder in relation to bipolar disorder or borderline personality disorder in adults |journal=[[Current Medical Research and Opinion]] |volume=30 |number=8 |pages=1657–1672 |doi=10.1185/03007995.2014.915800 |pmid=24804976}}|{{cite journal |vauthors=Philipsen A |title=Differential diagnosis and comorbidity of attention-deficit/hyperactivity disorder (ADHD) and borderline personality disorder (BPD) in adults |journal=[[European Archives of Psychiatry and Clinical Neuroscience]] |volume=256 |number=Supplement 1 |pages=i42–i46 |date=2006 |doi=10.1007/s00406-006-1006-2 |pmid=16977551}}}}</ref> The current diagnostic assessment of either disorder is often complex, as both have overlapping symptoms, thus these assessments can follow a differential diagnosis to determine whether there is a co-occurrence of both disorders or not.

Anxiety and mood disorders are frequent comorbidities. [[Anxiety disorder]]s have been found to occur more commonly in the ADHD population, as have [[mood disorder]]s (especially [[bipolar disorder]] and [[major depressive disorder]]).<ref name="Wilens_2010">{{cite journal |vauthors=Wilens TE, Spencer TJ |date=September 2010 |title=Understanding attention-deficit/hyperactivity disorder from childhood to adulthood |journal=Postgraduate Medicine |volume=122 |issue=5 |pages=97–109 |doi=10.3810/pgm.2010.09.2206 |pmc=3724232 |pmid=20861593}}</ref> While boys tend to present with comorbidities that involve externalization, girls tend to internalise their symptoms, leading to the possibility of increased misdiagnosis via standards designed to recognise male ADHD.<ref>{{Cite journal |last1=Skogli |first1=Erik Winther |last2=Teicher |first2=Martin H. |last3=Andersen |first3=Per Normann |last4=Hovik |first4=Kjell Tore |last5=Øie |first5=Merete |date=9 November 2013 |title=ADHD in girls and boys--gender differences in co-existing symptoms and executive function measures |journal=BMC Psychiatry |volume=13 |article-number=298 |doi=10.1186/1471-244X-13-298 |doi-access=free |issn=1471-244X |pmc=3827008 |pmid=24206839}}</ref><ref>{{Cite journal |last1=Mowlem |first1=Florence D. |last2=Rosenqvist |first2=Mina A. |last3=Martin |first3=Joanna |last4=Lichtenstein |first4=Paul |last5=Asherson |first5=Philip |last6=Larsson |first6=Henrik |date=April 2019 |title=Sex differences in predicting ADHD clinical diagnosis and pharmacological treatment |journal=European Child & Adolescent Psychiatry |volume=28 |issue=4 |pages=481–489 |doi=10.1007/s00787-018-1211-3 |issn=1435-165X |pmc=6445815 |pmid=30097723}}</ref> Adults and children with ADHD sometimes also have bipolar disorder, which requires careful assessment to accurately diagnose and treat both conditions.<ref name="pmid21717696">{{cite journal |vauthors=Baud P, Perroud N, Aubry JM |date=June 2011 |title=[Bipolar disorder and attention deficit/hyperactivity disorder in adults: differential diagnosis or comorbidity] |journal=[[Revue Médicale Suisse]] |language=fr |volume=7 |issue=297 |pages=1219–1222 |doi=10.53738/REVMED.2011.7.297.1219 |pmid=21717696}}</ref><ref name="Wilens_2011">{{cite journal |vauthors=Wilens TE, Morrison NR |date=July 2011 |title=The intersection of attention-deficit/hyperactivity disorder and substance abuse |journal=Current Opinion in Psychiatry |volume=24 |issue=4 |pages=280–285 |doi=10.1097/YCO.0b013e328345c956 |pmc=3435098 |pmid=21483267}}</ref>

[[Sleep disorders]] and ADHD commonly co-exist. They can also occur as a side effect of medications used to treat ADHD. In children with ADHD, [[insomnia]] is the most common sleep disorder with behavioural therapy being the preferred treatment.<ref name="pmid21600348">{{cite journal |vauthors=Corkum P, Davidson F, Macpherson M |date=June 2011 |title=A framework for the assessment and treatment of sleep problems in children with attention-deficit/hyperactivity disorder |journal=Pediatric Clinics of North America |volume=58 |issue=3 |pages=667–683 |doi=10.1016/j.pcl.2011.03.004 |pmid=21600348}}</ref><ref name="pmid20451036">{{cite journal |vauthors=Tsai MH, Huang YS |date=May 2010 |title=Attention-deficit/hyperactivity disorder and sleep disorders in children |journal=The Medical Clinics of North America |volume=94 |issue=3 |pages=615–632 |doi=10.1016/j.mcna.2010.03.008 |pmid=20451036}}</ref> Problems with sleep initiation are common among individuals with ADHD but often they will be deep sleepers and have significant difficulty getting up in the morning.<ref name="Brown_2008" /> [[Melatonin]] is sometimes used in children who have sleep onset insomnia.<ref name="pmid20028959">{{cite journal |vauthors=Bendz LM, Scates AC |date=January 2010 |title=Melatonin treatment for insomnia in pediatric patients with attention-deficit/hyperactivity disorder |journal=The Annals of Pharmacotherapy |volume=44 |issue=1 |pages=185–191 |doi=10.1345/aph.1M365 |pmid=20028959 |s2cid=207263711}}</ref> [[Restless legs syndrome]] has been found to be more common in those with ADHD and is often due to [[iron deficiency anemia]].<ref name="pmid21365608">{{cite journal |vauthors=Merino-Andreu M |date=March 2011 |title=Trastorno por déficit de atención/hiperactividad y síndrome de piernas inquietas en niños |trans-title=Attention deficit hyperactivity disorder and restless legs syndrome in children |journal=Revista de Neurologia |language=es |volume=52 |issue=Suppl 1 |pages=S85–S95 |doi=10.33588/rn.52S01.2011037 |pmid=21365608}}</ref><ref name="pmid20620105">{{cite journal |vauthors=Picchietti MA, Picchietti DL |date=August 2010 |title=Advances in pediatric restless legs syndrome: Iron, genetics, diagnosis and treatment |journal=Sleep Medicine |volume=11 |issue=7 |pages=643–651 |doi=10.1016/j.sleep.2009.11.014 |pmid=20620105}}</ref> However, restless legs can simply be a part of ADHD and requires careful assessment to differentiate between the two disorders.<ref name="pmid18656214">{{cite journal |vauthors=Karroum E, Konofal E, Arnulf I |year=2008 |title=[Restless-legs syndrome] |journal=Revue Neurologique |language=fr |volume=164 |issue=8–9 |pages=701–721 |doi=10.1016/j.neurol.2008.06.006 |pmid=18656214}}</ref> [[Delayed sleep phase disorder]] is also a common comorbidity.<ref>{{cite journal |vauthors=Wajszilber D, Santiseban JA, Gruber R |date=December 2018 |title=Sleep disorders in patients with ADHD: impact and management challenges |journal=Nature and Science of Sleep |volume=10 |pages=453–480 |doi=10.2147/NSS.S163074 |pmc=6299464 |pmid=30588139 |doi-access=free}}</ref>

Individuals with ADHD are at increased risk of [[substance use disorder]]s.<ref name="use" />{{rp|9|quote=Comorbid substance use disorder (SUD) deserves special attention due to the high rates of ADHD within SUD populations. A bidirectional link between ADHD and SUD is reported with ADHD symptoms over represented in SUD populations and SUD in ADHD populations.}} This is most commonly seen with [[Alcohol (drug)|alcohol]] or [[cannabis (drug)|cannabis]].<ref name="Kooij_2010" />{{rp|9|quote=Alcohol and cannabis are the most frequently abused substances in these populations followed by lower rates of cocaine and amphetamine abuse.}} The reason for this may be an altered reward pathway in the brains of ADHD individuals, self-treatment and increased psychosocial risk factors.{{rp|9|quote=The causes for such comorbidity are likely to be complex including altered reward processing in ADHD, increased exposure to psychosocial risk factors and self treatment.}} This makes the evaluation and treatment of ADHD more difficult, with serious substance misuse problems usually treated first due to their greater risks.<ref name="NICE2009-part2" /> Other psychiatric conditions include [[reactive attachment disorder]],<ref>{{cite journal |vauthors=Storebø OJ, Rasmussen PD, Simonsen E |date=February 2016 |title=Association Between Insecure Attachment and ADHD: Environmental Mediating Factors |url=https://findresearcher.sdu.dk:8443/ws/files/134088245/Association_Between_Insecure_Attachment_and_ADHD.pdf |url-status=live |journal=[[Journal of Attention Disorders]] |volume=20 |issue=2 |pages=187–196 |doi=10.1177/1087054713501079 |pmid=24062279 |s2cid=23564305 |archive-url=https://web.archive.org/web/20211209135025/https://findresearcher.sdu.dk:8443/ws/files/134088245/Association_Between_Insecure_Attachment_and_ADHD.pdf |archive-date=9 December 2021 |access-date=22 November 2021}}</ref> characterised by a severe inability to appropriately relate socially, and [[cognitive disengagement syndrome]], a distinct attention disorder occurring in 30–50% of ADHD cases as a comorbidity, regardless of the presentation; a subset of cases diagnosed with ADHD-PIP have been found to have CDS instead.<ref>{{cite journal |vauthors=Becker SP, Willcutt EG, Leopold DR, Fredrick JW, Smith ZR, Jacobson LA, Burns GL, Mayes SD, Waschbusch DA, Froehlich TE, McBurnett K, Servera M, Barkley RA |date=June 2023 |title=Report of a Work Group on Sluggish Cognitive Tempo: Key Research Directions and a Consensus Change in Terminology to Cognitive Disengagement Syndrome |journal=[[Journal of the American Academy of Child and Adolescent Psychiatry]] |volume=62 |issue=6 |pages=629–645 |doi=10.1016/j.jaac.2022.07.821 |pmc=9943858 |pmid=36007816}}</ref><ref>{{cite journal |author-link=Russell Barkley |vauthors=Barkley RA |date=January 2014 |title=Sluggish cognitive tempo (concentration deficit disorder?): current status, future directions, and a plea to change the name |url=https://psychology.uiowa.edu/sites/psychology.uiowa.edu/files/groups/nikolas/files/Barkley,%202014.pdf |url-status=live |journal=[[Journal of Abnormal Child Psychology]] |volume=42 |issue=1 |pages=117–125 |doi=10.1007/s10802-013-9824-y |pmid=24234590 |s2cid=8287560 |archive-url=https://web.archive.org/web/20170809102631/https://psychology.uiowa.edu/sites/psychology.uiowa.edu/files/groups/nikolas/files/Barkley,%202014.pdf |archive-date=9 August 2017}}</ref> Individuals with ADHD are three times more likely to be diagnosed with an [[eating disorder]] compared to those without ADHD; conversely, individuals with eating disorders are two times more likely to have ADHD than those without eating disorders.<ref name="Nazar_2016">{{cite journal |vauthors=Nazar BP, Bernardes C, Peachey G, Sergeant J, Mattos P, Treasure J |date=December 2016 |title=The risk of eating disorders comorbid with attention-deficit/hyperactivity disorder: A systematic review and meta-analysis |url=https://kclpure.kcl.ac.uk/portal/en/publications/the-risk-of-eating-disorders-comorbid-with-attentiondeficithyperactivity-disorder(9a8e868e-de6e-4e19-9561-f8a576836848).html |url-status=live |journal=The International Journal of Eating Disorders |volume=49 |issue=12 |pages=1045–1057 |doi=10.1002/eat.22643 |pmid=27859581 |s2cid=38002526 |archive-url=https://web.archive.org/web/20221208035350/https://kclpure.kcl.ac.uk/portal/en/publications/the-risk-of-eating-disorders-comorbid-with-attentiondeficithyperactivity-disorder(9a8e868e-de6e-4e19-9561-f8a576836848).html |archive-date=8 December 2022 |access-date=26 October 2022}}</ref>

===Trauma===
ADHD, [[Psychological trauma|trauma]], and [[adverse childhood experiences]] are also comorbid,<ref>{{cite journal |vauthors=Schneider M, VanOrmer J, Zlomke K |date=2019 |title=Adverse Childhood Experiences and Family Resilience Among Children with Autism Spectrum Disorder and Attention-Deficit/Hyperactivity Disorder |journal=[[Journal of Developmental and Behavioral Pediatrics]] |volume=40 |issue=8 |pages=573–580 |doi=10.1097/DBP.0000000000000703 |pmid=31335581 |s2cid=198193637}}</ref><ref>{{cite journal |vauthors=Moon DS, Bong SJ, Kim BN, Kang NR |date=January 2021 |title=Association between Maternal Adverse Childhood Experiences and Attention-Deficit/Hyperactivity Disorder in the Offspring: The Mediating Role of Antepartum Health Risks |journal=Soa--Ch'ongsonyon Chongsin Uihak = Journal of Child & Adolescent Psychiatry |volume=32 |issue=1 |pages=28–34 |doi=10.5765/jkacap.200041 |pmc=7788667 |pmid=33424239}}</ref> which could in part be potentially explained by the similarity in presentation between different diagnoses. The symptoms of ADHD and [[Post-traumatic stress disorder|PTSD]] can have significant behavioural overlap—in particular, motor restlessness, difficulty concentrating, distractibility, irritability/anger, emotional constriction or dysregulation, poor impulse control, and forgetfulness are common in both.<ref name="Ford_2009">{{Cite journal |vauthors=Ford JD, Connor DF |date=1 June 2009 |title=ADHD and post-traumatic stress disorder |journal=Current Attention Disorders Reports |volume=1 |issue=2 |pages=60–66 |doi=10.1007/s12618-009-0009-0 |issn=1943-457X |s2cid=145508751}}</ref><ref>{{cite journal |vauthors=Harrington KM, Miller MW, Wolf EJ, Reardon AF, Ryabchenko KA, Ofrat S |date=August 2012 |title=Attention-deficit/hyperactivity disorder comorbidity in a sample of veterans with posttraumatic stress disorder |journal=[[Comprehensive Psychiatry]] |volume=53 |issue=6 |pages=679–690 |doi=10.1016/j.comppsych.2011.12.001 |pmc=6519447 |pmid=22305866}}</ref> This could result in trauma-related disorders or ADHD being mis-identified as the other.<ref name="Szymanski_2011">{{Cite journal |vauthors=Szymanski K, Sapanski L, Conway F |date=1 January 2011 |title=Trauma and ADHD&nbsp;– Association or Diagnostic Confusion? A Clinical Perspective |journal=Journal of Infant, Child, and Adolescent Psychotherapy |location=Philadelphia PA |publisher=Taylor & Francis Group |volume=10 |issue=1 |pages=51–59 |doi=10.1080/15289168.2011.575704 |issn=1528-9168 |eissn=1940-9214 |s2cid=144348893}}</ref> Additionally, traumatic events in childhood are a risk factor for ADHD;<ref>{{cite journal |vauthors=Zhang N, Gao M, Yu J, Zhang Q, Wang W, Zhou C, Liu L, Sun T, Liao X, Wang J |date=October 2022 |title=Understanding the association between adverse childhood experiences and subsequent attention deficit hyperactivity disorder: A systematic review and meta-analysis of observational studies |journal=Brain and Behavior |volume=12 |issue=10 |article-number=e32748 |doi=10.1002/brb3.2748 |pmc=9575611 |pmid=36068993}}</ref><ref>{{cite journal |vauthors=Nguyen MN, Watanabe-Galloway S, Hill JL, Siahpush M, Tibbits MK, Wichman C |date=June 2019 |title=Ecological model of school engagement and attention-deficit/hyperactivity disorder in school-aged children |journal=[[European Child & Adolescent Psychiatry]] |volume=28 |issue=6 |pages=795–805 |doi=10.1007/s00787-018-1248-3 |pmid=30390147 |s2cid=53263217}}</ref> they can lead to structural brain changes and the development of ADHD behaviours.<ref name="Szymanski_2011" /> Finally, the behavioural consequences of ADHD symptoms cause a higher chance of the individual experiencing trauma (and therefore ADHD leads to a concrete diagnosis of a trauma-related disorder).<ref>{{Cite journal |vauthors=Miodus S, Allwood MA, Amoh N |date=5 January 2021 |title=Childhood ADHD Symptoms in Relation to Trauma Exposure and PTSD Symptoms Among College Students: Attending to and Accommodating Trauma |journal=[[Journal of Emotional and Behavioral Disorders]] |volume=29 |issue=3 |pages=187–196 |doi=10.1177/1063426620982624 |issn=1063-4266 |s2cid=234159064}}</ref><ref>{{Cite web |title=Is It ADHD or Trauma? |url=https://childmind.org/article/is-it-adhd-or-trauma/ |archive-url=https://web.archive.org/web/20240418002257/https://childmind.org/article/is-it-adhd-or-trauma/ |archive-date=18 April 2024 |access-date=18 April 2024 |website=Child Mind Institute}}</ref>

===Non-psychiatric===
{{see also|Accident-proneness#Hypophobia}}

Some non-psychiatric conditions are also comorbidities of ADHD. This includes [[epilepsy]],<ref name="NHS2018" /> a neurological condition characterised by recurrent seizures.<ref>{{cite journal |vauthors=Williams AE, Giust JM, Kronenberger WG, Dunn DW |date=2016 |title=Epilepsy and attention-deficit hyperactivity disorder: links, risks, and challenges |journal=[[Neuropsychiatric Disease and Treatment]] |volume=12 |pages=287–296 |doi=10.2147/NDT.S81549 |pmc=4755462 |pmid=26929624 |doi-access=free}}</ref><ref>{{cite journal |vauthors=Silva RR, Munoz DM, Alpert M |date=March 1996 |title=Carbamazepine use in children and adolescents with features of attention-deficit hyperactivity disorder: a meta-analysis |journal=[[Journal of the American Academy of Child and Adolescent Psychiatry]] |volume=35 |issue=3 |pages=352–358 |doi=10.1097/00004583-199603000-00017 |pmid=8714324 |doi-access=free}}</ref> There are well established associations between ADHD and obesity, [[asthma]] and sleep disorders,<ref name="pmid27664125">{{cite journal |vauthors=Instanes JT, Klungsøyr K, Halmøy A, Fasmer OB, Haavik J |date=February 2018 |title=Adult ADHD and Comorbid Somatic Disease: A Systematic Literature Review |journal=[[Journal of Attention Disorders]] |type=Systematic Review |volume=22 |issue=3 |pages=203–228 |doi=10.1177/1087054716669589 |pmc=5987989 |pmid=27664125}}</ref> and an association with celiac disease.<ref>{{cite journal |vauthors=Gaur S |date=May 2022 |title=The Association between ADHD and Celiac Disease in Children |journal=Children |publisher=[[MDPI]] |volume=9 |issue=6 |page=781 |doi=10.3390/children9060781 |pmc=9221618 |pmid=35740718 |doi-access=free}}</ref> Children with ADHD have a higher risk for [[migraine]] headaches,<ref>{{cite journal |vauthors=Hsu TW, Chen MH, Chu CS, Tsai SJ, Bai YM, Su TP, Chen TJ, Liang CS |date=May 2022 |title=Attention deficit hyperactivity disorder and risk of migraine: A nationwide longitudinal study |journal=Headache |volume=62 |issue=5 |pages=634–641 |doi=10.1111/head.14306 |pmid=35524451 |s2cid=248553863}}</ref> but have no increased risk of tension-type headaches. Children with ADHD may also experience headaches as a result of medication.<ref name="Salem_2017">{{cite journal |vauthors=Salem H, Vivas D, Cao F, Kazimi IF, Teixeira AL, Zeni CP |date=March 2018 |title=ADHD is associated with migraine: a systematic review and meta-analysis |journal=[[European Child & Adolescent Psychiatry]] |publisher=Springer Science and Business Media LLC |volume=27 |issue=3 |pages=267–277 |doi=10.1007/s00787-017-1045-4 |pmid=28905127 |s2cid=3949012}}</ref><ref name="Pan_2021">{{cite journal |vauthors=Pan PY, Jonsson U, Şahpazoğlu Çakmak SS, Häge A, Hohmann S, Nobel Norrman H, Buitelaar JK, Banaschewski T, Cortese S, Coghill D, Bölte S |date=January 2022 |title=Headache in ADHD as comorbidity and a side effect of medications: a systematic review and meta-analysis |journal=Psychological Medicine |publisher=[[Cambridge University Press]] |volume=52 |issue=1 |pages=14–25 |doi=10.1017/s0033291721004141 |pmc=8711104 |pmid=34635194 |doi-access=free}}</ref>

A 2021 review reported that several neurometabolic disorders caused by [[inborn errors of metabolism]] converge on common neurochemical mechanisms that interfere with biological mechanisms also considered central in ADHD pathophysiology and treatment. This highlights the importance of close collaboration between health services to avoid clinical overshadowing.<ref>{{cite journal |vauthors=Cannon Homaei S, Barone H, Kleppe R, Betari N, Reif A, Haavik J |date=January 2022 |title=ADHD symptoms in neurometabolic diseases: Underlying mechanisms and clinical implications |journal=[[Neuroscience & Biobehavioral Reviews]] |volume=132 |pages=838–856 |doi=10.1016/j.neubiorev.2021.11.012 |pmid=34774900 |s2cid=243983688 |doi-access=free}}</ref>

In June 2021, ''[[Neuroscience & Biobehavioral Reviews]]'' published a [[systematic review]] of 82 studies that all confirmed or implied elevated accident-proneness in ADHD patients, and whose data suggested that the type of accidents or injuries—and overall risk—changes over the lifespan of ADHD patients.<ref>{{cite journal |vauthors=Brunkhorst-Kanaan N, Libutzki B, Reif A, Larsson H, McNeill RV, Kittel-Schneider S |date=June 2021 |title=ADHD and accidents over the life span - A systematic review |journal=[[Neuroscience & Biobehavioral Reviews]] |publisher=[[Elsevier]] |volume=125 |pages=582–591 |doi=10.1016/j.neubiorev.2021.02.002 |pmid=33582234 |s2cid=231885131 |doi-access=free}}</ref> In January 2014, ''[[Accident Analysis & Prevention]]'' published a [[meta-analysis]] of 16 studies examining the relative risk of [[traffic collision]]s for drivers with ADHD, finding an overall relative risk estimate of 1.36 without controlling for exposure, a relative risk estimate of 1.29 when controlling for [[publication bias]], a relative risk estimate of 1.23 when controlling for exposure, and a relative risk estimate of 1.86 for ADHD drivers with [[oppositional defiant disorder]] or [[conduct disorder]] [[Comorbidity|comorbidities]].<ref>{{cite journal |vauthors=Vaa T |date=January 2014 |title=ADHD and relative risk of accidents in road traffic: a meta-analysis |journal=[[Accident Analysis & Prevention]] |publisher=[[Elsevier]] |volume=62 |pages=415–425 |doi=10.1016/j.aap.2013.10.003 |pmid=24238842 |hdl-access=free |hdl=11250/2603537}}</ref><ref>{{Cite web |date=1 June 2018 |title=Overview: Attention deficit hyperactivity disorder (ADHD) |url=https://www.nhs.uk/conditions/attention-deficit-hyperactivity-disorder-adhd/ |archive-url=https://web.archive.org/web/20240217091056/https://www.nhs.uk/conditions/attention-deficit-hyperactivity-disorder-adhd/ |archive-date=17 February 2024 |access-date=16 February 2024 |website=[[NHS]]}}</ref>

===Problematic digital media use===
{{See also|Screen time|Internet addiction disorder|Problematic smartphone use|Problematic social media use|Video game addiction}}
{{Excerpt|Digital media use and mental health|ADHD}}

===Suicide risk===
Systematic reviews in 2017 and 2020 found strong evidence that ADHD is associated with increased [[suicide]] risk across all age groups, as well as growing evidence that an ADHD diagnosis in childhood or adolescence represents a significant future suicidal risk factor.<ref>{{cite journal |vauthors=Balazs J, Kereszteny A |date=March 2017 |title=Attention-deficit/hyperactivity disorder and suicide: A systematic review |journal=World Journal of Psychiatry |volume=7 |issue=1 |pages=44–59 |doi=10.5498/wjp.v7.i1.44 |pmc=5371172 |pmid=28401048 |doi-access=free}}</ref><ref name="Garas_2020">{{cite journal |vauthors=Garas P, Balazs J |date=21 December 2020 |title=Long-Term Suicide Risk of Children and Adolescents With Attention Deficit and Hyperactivity Disorder-A Systematic Review |journal=[[Frontiers in Psychiatry]] |volume=11 |article-number=557909 |doi=10.3389/fpsyt.2020.557909 |pmc=7779592 |pmid=33408650 |id=557909 |doi-access=free}}</ref> Potential causes include ADHD's association with functional impairment, negative social, educational and occupational outcomes, and financial distress.<ref name="Septier_2019">{{cite journal |vauthors=Septier M, Stordeur C, Zhang J, Delorme R, Cortese S |date=August 2019 |title=Association between suicidal spectrum behaviors and Attention-Deficit/Hyperactivity Disorder: A systematic review and meta-analysis |url=https://eprints.soton.ac.uk/431399/1/Septier_et_al_ADHD_SUICIDE_R2_CLEANED.docx |url-status=live |journal=[[Neuroscience & Biobehavioral Reviews]] |volume=103 |pages=109–118 |doi=10.1016/j.neubiorev.2019.05.022 |pmid=31129238 |s2cid=162184004 |archive-url=https://web.archive.org/web/20211104140233/https://eprints.soton.ac.uk/431399/1/Septier_et_al_ADHD_SUICIDE_R2_CLEANED.docx |archive-date=4 November 2021 |access-date=7 December 2021}}</ref><ref>{{cite journal |vauthors=Beauchaine TP, Ben-David I, Bos M |date=September 2020 |title=ADHD, financial distress, and suicide in adulthood: A population study |journal=[[Science Advances]] |volume=6 |issue=40 |article-number=eaba1551 |bibcode=2020SciA....6.1551B |doi=10.1126/sciadv.aba1551 |pmc=7527218 |pmid=32998893 |id=eaba1551}}</ref> A 2019 meta-analysis indicated a significant association between ADHD and suicidal spectrum behaviours (suicidal attempts, ideations, plans, and completed suicides); across the studies examined, the prevalence of suicide attempts in individuals with ADHD was 18.9%, compared to 9.3% in individuals without ADHD, and the findings were substantially replicated among studies which adjusted for other variables. However, the relationship between ADHD and suicidal spectrum behaviours remains unclear due to mixed findings across individual studies and the complicating impact of comorbid psychiatric disorders.<ref name="Septier_2019" /> There is no clear data on whether there is a direct relationship between ADHD and suicidality, or whether ADHD increases suicide risk through comorbidities.<ref name="Garas_2020" />

===Rejection sensitive dysphoria===
Rejection sensitive dysphoria, while not a formal diagnosis, is a common symptom of ADHD, estimated to affect a majority of people with ADHD.<ref>{{Cite journal |last=Bedrossian |first=Louise |date=18 April 2021 |title=Understand and address complexities of rejection sensitive dysphoria in students with ADHD |url=https://onlinelibrary.wiley.com/doi/10.1002/dhe.31047 |journal=Disability Compliance for Higher Education |language=en |volume=26 |issue=10 |page=4 |doi=10.1002/dhe.31047 |issn=1086-1335 |s2cid=234849318 |url-access=subscription}}</ref><ref>{{cite magazine |vauthors=Dodson W |date=28 February 2020 |title=How ADHD Ignites RSD: Meaning & Medication Solutions |magazine=[[Additude Magazine]] |url=https://www.additudemag.com/rejection-sensitive-dysphoria-and-adhd/}}</ref><ref>{{Cite journal |last1=Ginapp |first1=Callie M. |last2=Greenberg |first2=Norman R. |last3=MacDonald-Gagnon |first3=Grace |last4=Angarita |first4=Gustavo A. |last5=Bold |first5=Krysten W. |last6=Potenza |first6=Marc N. |date=12 October 2023 |title='Dysregulated not deficit': A qualitative study on symptomatology of ADHD in young adults |journal=[[PLOS ONE]] |language=en |volume=18 |issue=10 |article-number=e0292721 |doi=10.1371/journal.pone.0292721 |pmc=10569543 |pmid=37824501 |doi-access=free}}</ref> Others posit that rejection sensitivity stems from early [[Attachment in children|attachment relationships]] and parental rejection;<ref name="Butler">{{cite journal |last1=Butler |first1=J. C. |last2=Doherty |first2=M. S. |last3=Potter |first3=R. M. |year=2007 |title=Social antecedents and consequences of interpersonal rejection sensitivity |url=http://www.smsu.edu/facultystaff/jamesbutler/rejectsensitivity.pdf |journal=[[Personality and Individual Differences]] |volume=43 |issue=6 |pages=1376–1385 |doi=10.1016/j.paid.2007.04.006 |archive-url=https://web.archive.org/web/20140602200751/http://www.smsu.edu/facultystaff/jamesbutler/rejectsensitivity.pdf |archive-date=2 June 2014 }}</ref> peer rejection is also thought to play a role.<ref name="Butler" /><ref name="London-social">{{cite journal |last1=London |first1=B. |last2=Downey |first2=G. |last3=Bonica |first3=C. |last4=Paltin |first4=I. |year=2007 |title=Social causes and consequences of rejection sensitivity |journal=[[Journal of Research on Adolescence]] |volume=17 |issue=3 |pages=481–506 |doi=10.1111/j.1532-7795.2007.00531.x}}</ref> Bullying, an extreme form of peer rejection, is likely connected to later rejection sensitivity.<ref name="Butler" /> However, there is no conclusive evidence for any of these theories.<ref name="Butler" />

[[Karen Horney]] was the first theorist to discuss the phenomenon of ''rejection sensitivity''.<ref>Downey, G. (2008). The disregulating effect of social threat in people with borderline personality disorder. Paper presented at the Annual Meeting of the Society for Personality and Social Psychology, February 7–9, 2008.</ref> She suggested that it is a component of the [[neuroticism|neurotic]] personality, and that it is a tendency to feel deep anxiety and humiliation at the slightest rebuff. Simply being made to wait, for example, could be viewed as a rejection and met with extreme anger and hostility.<ref>[[Karen Horney|Horney, K.]] (1937). ''The neurotic personality of our time''. New York: W. W. Norton and Company.</ref>

[[Albert Mehrabian]] developed an early questionnaire measure of rejection sensitivity.<ref>{{cite journal |last1=Mehrabian |first1=Albert |author-link=Albert Mehrabian |year=1976 |title=Questionnaire measures of affiliative tendency and sensitivity to rejection |journal=Psychological Reports |volume=38 |pages=199–209 |doi=10.2466/pr0.1976.38.1.199 |s2cid=144417099}}</ref> Mehrabian suggested that sensitive individuals are reluctant to express opinions, tend to avoid arguments or controversial discussions, are reluctant to make requests or impose on others, are easily hurt by negative feedback from others, and tend to rely too much on familiar others and situations so as to avoid rejection.

A more recent (1996) definition of rejection sensitivity is the tendency to "anxiously expect, readily perceive, and overreact" to social rejection.<ref name="pmid8667172">{{cite journal|vauthors=Downey G, Feldman SI |title=Implications of rejection sensitivity for intimate relationships |journal=J Pers Soc Psychol |url=http://www.ffri.uniri.hr/~ibrdar/komunikacija/seminari/Downey,%201996%20-%20Rejection%20Sensitivity%20for%20intimate%20relationsh.pdf |year=1996 |volume=70 |issue=6 |pages=1327–43 |pmid=8667172 |doi=10.1037/0022-3514.70.6.1327 |s2cid=7822358 |archive-url=https://web.archive.org/web/20130731044210/http://www.ffri.uniri.hr/~ibrdar/komunikacija/seminari/Downey,%201996%20-%20Rejection%20Sensitivity%20for%20intimate%20relationsh.pdf |archive-date=July 31, 2013 }}</ref> People differ in their readiness to perceive and react to rejection.<ref name="pmid8667172"/> The causes of individual differences in rejection sensitivity are not well understood. Because of the association between rejection sensitivity and neuroticism, there is a likely genetic predisposition.<ref name="Butler" />

==Management==
{{Main|Management of attention deficit hyperactivity disorder}}

The management of ADHD typically involves [[psychotherapy|counseling]] or medications, either alone or in combination. While there are various options of treatment to improve ADHD symptoms, medication therapies substantially improve long-term outcomes, and while eliminating some elevated risks such as obesity,<ref name="Faraone_2021" /> they do come with some risks of adverse events.<ref>{{cite journal |vauthors=Peterson BS, Trampush J, Maglione M, Bolshakova M, Rozelle M, Miles J, Pakdaman S, Brown M, Yagyu S, Motala A, Hempel S |title=Treatments for ADHD in Children and Adolescents: A Systematic Review |journal=[[Pediatrics (journal)|Pediatrics]] |volume=153 |issue=4 |date=April 2024 |article-number=e2024065787 |pmid=38523592 |doi=10.1542/peds.2024-065787}}</ref> Medications used include stimulants, atomoxetine, [[alpha-2 adrenergic receptor]] agonists, and sometimes antidepressants.<ref name="Wilens_2010" /><ref name="cognition enhancers">{{cite journal |vauthors=Bidwell LC, McClernon FJ, Kollins SH |title=Cognitive enhancers for the treatment of ADHD |journal=[[Pharmacology Biochemistry and Behavior]] |volume=99 |issue=2 |pages = 262–274 |date=August 2011 |pmid=21596055 |pmc=3353150 |doi=10.1016/j.pbb.2011.05.002}}</ref> In those who have trouble focusing on long-term rewards, a large amount of [[positive reinforcement]] improves task performance.<ref name="Motivation" /> Medications are the most effective treatment,<ref name="Faraone_2021" /><ref name="CNS09">{{cite journal |vauthors=Wigal SB |title=Efficacy and safety limitations of attention-deficit hyperactivity disorder pharmacotherapy in children and adults |journal=[[CNS Drugs]] |volume=23 |issue=Suppl 1 |pages=21–31 |year=2009 |pmid=19621975 |doi=10.2165/00023210-200923000-00004 |s2cid=11340058}}</ref> and any side effects are typically mild and easy to resolve<ref name="Faraone_2021" /> although any improvements will be reverted if medication is ceased.<ref name="May_2008">{{cite journal |vauthors=Mayes R, Bagwell C, Erkulwater J |title=ADHD and the rise in stimulant use among children |journal=[[Harvard Review of Psychiatry]] |volume=16 |issue=3 |pages=151–166 |date=2008 |pmid=18569037 |doi=10.1080/10673220802167782 |s2cid=18481191}}</ref> ADHD stimulants also improve persistence and task performance in children with ADHD.<ref name="Malenka ADHD neurosci" /><ref name="Motivation" /> To quote one systematic review, "recent evidence from observational and registry studies indicates that pharmacological treatment of ADHD is associated with increased achievement and decreased absenteeism at school, a reduced risk of trauma-related emergency hospital visits, reduced risks of suicide and attempted suicide, and decreased rates of substance abuse and criminality".<ref name="Coghill_2017">{{cite journal |vauthors=Coghill DR, Banaschewski T, Soutullo C, Cottingham MG, Zuddas A |title=Systematic review of quality of life and functional outcomes in randomized placebo-controlled studies of medications for attention-deficit/hyperactivity disorder |journal=[[European Child & Adolescent Psychiatry]] |volume=26 |issue=11 |pages=1283–1307 |date=November 2017 |pmid=28429134 |pmc=5656703 |doi=10.1007/s00787-017-0986-y}} [[File:CC-BY icon.svg|50x50px]] Text was copied from this source, which is available under a [[creativecommons:by/4.0/|Creative Commons Attribution 4.0 International License]] {{Cite web |url=https://creativecommons.org/licenses/by/4.0/ |title=CC BY 4.0 Deed &#124; Attribution 4.0 International &#124; Creative Commons |access-date=22 October 2022 |archive-date=16 October 2017 |archive-url=https://web.archive.org/web/20171016050101/https://creativecommons.org/licenses/by/4.0/}}</ref> Data also suggest that combining medication with [[cognitive behavioral therapy]] (CBT) can have positive effects: although CBT is substantially less effective, it can help address problems that reside after medication has been optimised.<ref name="Faraone_2021" />
The nature and range of desirable endpoints of ADHD treatment vary among diagnostic standards for ADHD.<ref>{{cite journal |vauthors=Jummani RR, Hirsch E, Hirsch GS |title=Are We Overdiagnosing and Overtreating ADHD? |journal=[[Psychiatric Times]] |volume=34 |issue=5 |date=31 May 2019 |url=https://www.psychiatrictimes.com/view/are-we-overdiagnosing-and-overtreating-adhd}}</ref> In most studies, the efficacy of treatment is determined by reductions in symptoms.<ref>{{cite journal |vauthors=Luan R, Mu Z, Yue F, He S |title=Efficacy and Tolerability of Different Interventions in Children and Adolescents with Attention Deficit Hyperactivity Disorder |journal=[[Frontiers in Psychiatry]] |volume=8 |article-number=229 |date=2017 |pmid=29180967 |pmc=5694170 |doi=10.3389/fpsyt.2017.00229 |doi-access=free}}</ref> However, some studies have included subjective ratings from teachers and parents as part of their assessment of treatment efficacies.<ref name="Comparative efficacy and tolerabili"/>

===Behavioural therapies===
There is good evidence for the use of [[behavioural therapy|behavioural therapies]] in ADHD. They are the recommended first-line treatment in those who have mild symptoms or who are preschool-aged.<ref>{{cite journal |vauthors=Fabiano GA, Pelham WE, Coles EK, Gnagy EM, Chronis-Tuscano A, O'Connor BC |title=A meta-analysis of behavioral treatments for attention-deficit/hyperactivity disorder |journal=[[Clinical Psychology Review]] |volume=29 |issue=2 |pages=129–140 |date=March 2009 |pmid=19131150 |doi=10.1016/j.cpr.2008.11.001 |quote=there is strong and consistent evidence that behavioral treatments are effective for treating ADHD. |doi-access=free}}</ref><ref name="Clinics09">{{cite journal |vauthors=Kratochvil CJ, Vaughan BS, Barker A, Corr L, Wheeler A, Madaan V |title=Review of pediatric attention deficit/hyperactivity disorder for the general psychiatrist |journal=[[Psychiatric Clinics of North America]] |volume=32 |issue=1 |pages=39–56 |date=March 2009 |pmid=19248915 |doi=10.1016/j.psc.2008.10.001}}</ref> Psychological therapies used include: [[psychoeducation]]al input, behavior therapy, [[cognitive behavioral therapy]],<ref>{{cite journal |vauthors=Lopez PL, Torrente FM, Ciapponi A, Lischinsky AG, Cetkovich-Bakmas M, Rojas JI, Romano M, Manes FF |title=Cognitive-behavioural interventions for attention deficit hyperactivity disorder (ADHD) in adults |journal=[[The Cochrane Database of Systematic Reviews]] |volume=2018 |issue=3 |article-number=CD010840 |date=March 2018 |pmid=29566425 |pmc=6494390 |doi=10.1002/14651858.CD010840.pub2}}</ref> [[interpersonal psychotherapy]], [[family therapy]], school-based interventions, social skills training, behavioural peer intervention, organisation training,<ref name="Evans2014">{{cite journal |vauthors=Evans SW, Owens JS, Bunford N |title=Evidence-based psychosocial treatments for children and adolescents with attention-deficit/hyperactivity disorder |journal=[[Journal of Clinical Child and Adolescent Psychology]] |volume=43 |issue=4 |pages=527–551 |date=2014 |pmid=24245813 |pmc=4025987 |doi=10.1080/15374416.2013.850700}}</ref> and [[parent management training]].<ref name="NICE 2009" /> [[Neurofeedback]] has greater treatment effects than non-active controls for up to 6 months and possibly a year following treatment, and may have treatment effects comparable to active controls (controls proven to have a clinical effect) over that time period.<ref>{{cite journal |vauthors=Van Doren J, Arns M, Heinrich H, Vollebregt MA, Strehl U, K Loo S |title=Sustained effects of neurofeedback in ADHD: a systematic review and meta-analysis |journal=[[European Child & Adolescent Psychiatry]] |volume=28 |issue=3 |pages=293–305 |date=March 2019 |pmid=29445867 |pmc=6404655 |doi=10.1007/s00787-018-1121-4 |publisher=Springer Science and Business Media LLC}}</ref> Despite efficacy in research, there is insufficient regulation of neurofeedback practice, leading to ineffective applications and false claims regarding innovations.<ref>{{cite journal |vauthors=Enriquez-Geppert S, Smit D, Pimenta MG, Arns M |title=Neurofeedback as a Treatment Intervention in ADHD: Current Evidence and Practice |journal=[[Current Psychiatry Reports]] |volume=21 |issue=6 |article-number=46 |date=May 2019 |pmid=31139966 |pmc=6538574 |doi=10.1007/s11920-019-1021-4 |publisher=Springer Science and Business Media LLC}}</ref> Parent training may improve a number of behavioural problems including oppositional and non-compliant behaviours.<ref name="Dal2017">{{cite journal |vauthors=Daley D, Van Der Oord S, Ferrin M, Cortese S, Danckaerts M, Doepfner M, Van den Hoofdakker BJ, Coghill D, Thompson M, Asherson P, Banaschewski T, Brandeis D, Buitelaar J, Dittmann RW, Hollis C, Holtmann M, Konofal E, Lecendreux M, Rothenberger A, Santosh P, Simonoff E, Soutullo C, Steinhausen HC, Stringaris A, Taylor E, Wong IC, Zuddas A, Sonuga-Barke EJ |title=Practitioner Review: Current best practice in the use of parent training and other behavioural interventions in the treatment of children and adolescents with attention deficit hyperactivity disorder |journal=[[Journal of Child Psychology and Psychiatry|Journal of Child Psychology and Psychiatry, and Allied Disciplines]] |volume=59 |issue=9 |pages=932–947 |date=September 2018 |pmid=29083042 |doi=10.1111/jcpp.12825 |url=http://eprints.nottingham.ac.uk/45391/ |access-date=21 November 2018 |publisher=Wiley |url-status=live |hdl=11343/293788 |s2cid=31044370 |archive-url=https://web.archive.org/web/20170925140540/http://eprints.nottingham.ac.uk/45391/ |archive-date=25 September 2017 |hdl-access=free}}</ref>

There is little high-quality research on the effectiveness of family therapy for ADHD—but the existing evidence shows that it is similar to community care, and better than placebo.<ref>{{cite journal |vauthors=Bjornstad G, Montgomery P |title=Family therapy for attention-deficit disorder or attention-deficit/hyperactivity disorder in children and adolescents |journal=[[The Cochrane Database of Systematic Reviews]] |issue=2 |article-number=CD005042 |date=April 2005 |pmid=15846741 |doi=10.1002/14651858.CD005042.pub2 |veditors=Bjornstad GJ |s2cid=27339381}}</ref> ADHD-specific support groups can provide information and may help families cope with ADHD.<ref name="Brain encyclopedia">{{cite encyclopedia |vauthors=Turkington C, Harris J |title=Attention deficit hyperactivity disorder (ADHD) |url=https://books.google.com/books?id=6hbKkynRxPYC&pg=PA42 |encyclopedia=The Encyclopedia of the Brain and Brain Disorders |year=2009 |publisher=[[Infobase Publishing]] |isbn=978-1-4381-2703-3 |pages=[https://books.google.com/books?id=6hbKkynRxPYC&pg=PA47 47]}}</ref>

Social skills training, behavioural modification, and medication may have some limited beneficial effects in peer relationships. Stable, high-quality friendships with [[Deviance (sociology)|non-deviant]] peers protect against later psychological problems.<ref name="pmid20490677">{{cite journal |vauthors=Mikami AY |title=The importance of friendship for youth with attention-deficit/hyperactivity disorder |journal=[[Clinical Child and Family Psychology Review]] |volume=13 |issue=2 |pages=181–198 |date=June 2010 |pmid=20490677 |pmc=2921569 |doi=10.1007/s10567-010-0067-y}}</ref>

===Digital interventions===
Several clinical trials have investigated the efficacy of digital therapeutics, particularly Akili Interactive Labs's video game-based digital therapeutic AKL-T01, marketed as [[EndeavourRx]]. The pediatric STARS-ADHD randomised, double-blind, parallel-group, controlled trial demonstrated that AKL-T01 significantly improved performance on the [[Test of Variables of Attention]], an objective measure of attention and inhibitory control, compared to a control group after four weeks of at-home use.<ref name="STARS-ADHD">{{cite journal |vauthors=Kollins SH, DeLoss DJ, Cañadas E, Lutz J, Findling RL, Keefe RS, Epstein JN, Cutler AJ, Faraone SV |title=A novel digital intervention for actively reducing severity of paediatric ADHD (STARS-ADHD): a randomised controlled trial |journal=[[The Lancet Digital Health]] |volume=2 |issue=4 |pages=e168–e178 |date=April 2020 |pmid=33334505 |doi=10.1016/S2589-7500(20)30017-0 |doi-access=free}}</ref> A subsequent pediatric open-label study, STARS-Adjunct, published in [[Nature Portfolio]]'s [[npj Digital Medicine]] evaluated AKL-T01 as an adjunctive treatment for children with ADHD who were either on stimulant medication or not on stimulant pharmacotherapy. Results showed improvements in ADHD-related impairment (measured by the Impairment Rating Scale) and ADHD symptoms after 4 weeks of treatment, with effects persisting during a 4-week pause and further improving with an additional treatment period.<ref name="STARS-ADHD-Adjunct">{{cite journal |vauthors=Kollins SH, Childress A, Heusser AC, Lutz J |title=Effectiveness of a digital therapeutic as adjunct to treatment with medication in pediatric ADHD |journal=npj Digital Medicine |volume=4 |issue=1 |article-number=58 |date=March 2021 |pmid=33772095 |pmc=7997870 |doi=10.1038/s41746-021-00429-0 |ref=STARS-Adjunct}}</ref> Notably, the magnitude of the measured improvement was similar for children both on and off stimulants.<ref name="STARS-ADHD-Adjunct" /> In 2020, AKL-T01 received marketing authorisation for pediatric ADHD from the [[Food and Drug Administration|FDA]], becoming "the first game-based therapeutic granted marketing authorisation by the FDA for any type of condition."<ref name="FDA AKL-T01">{{cite web |title=FDA Permits Marketing of First Game-Based Digital Therapeutic to Improve Attention Function in Children with ADHD |url=https://www.fda.gov/news-events/press-announcements/fda-permits-marketing-first-game-based-digital-therapeutic-improve-attention-function-children-adhd |archive-url=https://web.archive.org/web/20200616075516/https://www.fda.gov/news-events/press-announcements/fda-permits-marketing-first-game-based-digital-therapeutic-improve-attention-function-children-adhd |archive-date=16 June 2020 |website=Food and Drug Administration |date=17 June 2020 |publisher=United States Food and Drug Administration |access-date=19 April 2024 |ref=FDA}}</ref>

In addition to pediatric populations, a 2023 study in the ''[[Journal of the American Academy of Child and Adolescent Psychiatry|Journal of the American Academy of Child & Adolescent Psychiatry]]'' investigated the efficacy and safety of AKL-T01 in adults with ADHD. After six weeks of at-home treatment with AKL-T01, participants showed significant improvements in objective measures of attention ([[Test of Variables of Attention|TOVA - Attention Comparison Score]]), reported ADHD symptoms (ADHD-RS-IV inattention subscale and total score), and reported quality of life (AAQoL).<ref name="STARS-ADHD-Adults">{{cite journal |vauthors=Stamatis CA, Mercaldi C, Kollins SH |title=A Single-Arm Pivotal Trial to Assess the Efficacy of Akl-T01, a Novel Digital Intervention for Attention, in Adults Diagnosed With ADHD |journal=[[Journal of the American Academy of Child and Adolescent Psychiatry]] |date=October 2023 |volume=62 |issue=10 |pages=S318 |doi=10.1016/j.jaac.2023.09.510 |url=https://www.jaacap.org/article/S0890-8567(23)01994-9/fulltext#%20 |access-date=22 April 2024}}</ref> The magnitude of improvement in attention was nearly seven times greater than that reported in pediatric trials.<ref name="STARS-ADHD-Adults" /> The treatment was well-tolerated, with high compliance and no serious adverse events.<ref name="STARS-ADHD-Adults" />

===Medication===
The medications for ADHD appear to alleviate symptoms via their effects on the pre-frontal executive, striatal and related regions and networks in the brain; usually by increasing neurotransmission of [[norepinephrine]] and [[dopamine]].<ref>{{cite journal |vauthors=Devilbiss DM, Berridge CW |title=Cognition-enhancing doses of methylphenidate preferentially increase prefrontal cortex neuronal responsiveness |journal=[[Biological Psychiatry (journal)|Biological Psychiatry]] |volume=64 |issue=7 |pages=626–635 |date=October 2008 |pmid=18585681 |pmc=2603602 |doi=10.1016/j.biopsych.2008.04.037}}</ref><ref name="Schulz_2012">{{cite journal |vauthors=Schulz KP, Fan J, Bédard AC, Clerkin SM, Ivanov I, Tang CY, Halperin JM, Newcorn JH |title=Common and unique therapeutic mechanisms of stimulant and nonstimulant treatments for attention-deficit/hyperactivity disorder |journal=Archives of General Psychiatry |volume=69 |issue=9 |pages=952–961 |date=September 2012 |pmid=22945622 |doi=10.1001/archgenpsychiatry.2011.2053}}</ref><ref name="Koda_2010">{{cite journal |vauthors=Koda K, Ago Y, Cong Y, Kita Y, Takuma K, Matsuda T |title=Effects of acute and chronic administration of atomoxetine and methylphenidate on extracellular levels of noradrenaline, dopamine and serotonin in the prefrontal cortex and striatum of mice |journal=[[Journal of Neurochemistry]] |volume=114 |issue=1 |pages=259–270 |date=July 2010 |pmid=20403082 |doi=10.1111/j.1471-4159.2010.06750.x}}</ref>

According to Effective Health Care Systematic Review, FDA-approved stimulant and non-stimulant medications shows sufficient evidence showing that they greatly improve the core symptoms of ADHD.<ref>{{Cite web |url=https://effectivehealthcare.ahrq.gov/products/attention-deficit-hyperactivity-disorder/research |access-date=2025-11-16 |website=effectivehealthcare.ahrq.gov}}</ref>

====Stimulants====
[[Methylphenidate]] and [[amphetamine]] or its derivatives are often first-line treatments for ADHD.<ref name="Dodson_2005" /><ref>{{cite journal |vauthors=Storebø OJ, Storm MR, Pereira Ribeiro J, Skoog M, Groth C, Callesen HE, Schaug JP, Darling Rasmussen P, Huus CL, Zwi M, Kirubakaran R, Simonsen E, Gluud C |title=Methylphenidate for children and adolescents with attention deficit hyperactivity disorder (ADHD) |journal=[[The Cochrane Database of Systematic Reviews]] |volume=2023 |issue=3 |article-number=CD009885 |date=March 2023 |pmid=36971690 |pmc=10042435 |doi=10.1002/14651858.CD009885.pub3}}</ref> About 70 per cent respond to the first stimulant tried and as few as 10 per cent respond to neither amphetamines nor methylphenidate.<ref name="CNS09" /> Stimulants may also reduce the risk of unintentional injuries in children with ADHD.<ref name="Ruiz-Goikoetxea_2017">{{cite journal |vauthors=Ruiz-Goikoetxea M, Cortese S, Aznarez-Sanado M, Magallón S, Alvarez Zallo N, Luis EO, de Castro-Manglano P, Soutullo C, Arrondo G |title=Risk of unintentional injuries in children and adolescents with ADHD and the impact of ADHD medications: A systematic review and meta-analysis |journal=[[Neuroscience & Biobehavioral Reviews]] |volume=84 |pages=63–71 |date=January 2018 |pmid=29162520 |doi=10.1016/j.neubiorev.2017.11.007 |hdl-access=free |doi-access=free |hdl=10171/45012}}</ref> [[Magnetic resonance imaging]] studies suggest that long-term treatment with amphetamine or methylphenidate decreases abnormalities in brain structure and function found in subjects with ADHD.<ref name="Neuroplasticity 1">{{cite journal |vauthors=Hart H, Radua J, Nakao T, Mataix-Cols D, Rubia K |title=Meta-analysis of functional magnetic resonance imaging studies of inhibition and attention in attention-deficit/hyperactivity disorder: exploring task-specific, stimulant medication, and age effects |journal=[[JAMA Psychiatry]] |volume=70 |issue=2 |pages=185–198 |date=February 2013 |pmid=23247506 |doi=10.1001/jamapsychiatry.2013.277 |doi-access=free}}</ref><ref name="Neuroplasticity 2">{{cite journal |vauthors=Spencer TJ, Brown A, Seidman LJ, Valera EM, Makris N, Lomedico A, Faraone SV, Biederman J |title=Effect of psychostimulants on brain structure and function in ADHD: a qualitative literature review of magnetic resonance imaging-based neuroimaging studies |journal=[[The Journal of Clinical Psychiatry]] |volume=74 |issue=9 |pages=902–917 |date=September 2013 |pmid=24107764 |pmc=3801446 |doi=10.4088/JCP.12r08287}}</ref><ref name="Neuroplasticity 3">{{cite journal |vauthors=Frodl T, Skokauskas N |title=Meta-analysis of structural MRI studies in children and adults with attention deficit hyperactivity disorder indicates treatment effects |journal=[[Acta Psychiatrica Scandinavica]] |volume=125 |issue=2 |pages=114–126 |date=February 2012 |pmid=22118249 |doi=10.1111/j.1600-0447.2011.01786.x |quote=Basal ganglia regions like the right globus pallidus, the right putamen, and the nucleus caudatus are structurally affected in children with ADHD. These changes and alterations in limbic regions like {{abbr|ACC|anterior cingulate cortex}} and amygdala are more pronounced in non-treated populations and seem to diminish over time from child to adulthood. Treatment seems to have positive effects on brain structure. |s2cid=25954331 |doi-access=free}}</ref> A 2018 review found the greatest short-term benefit with methylphenidate in children, and amphetamines in adults.<ref name="Comparative efficacy and tolerabili">{{cite journal |vauthors=Cortese S, Adamo N, Del Giovane C, Mohr-Jensen C, Hayes AJ, Carucci S, Atkinson LZ, Tessari L, Banaschewski T, Coghill D, Hollis C, Simonoff E, Zuddas A, Barbui C, Purgato M, Steinhausen HC, Shokraneh F, Xia J, Cipriani A |title=Comparative efficacy and tolerability of medications for attention-deficit hyperactivity disorder in children, adolescents, and adults: a systematic review and network meta-analysis |journal=[[The Lancet Psychiatry]] |volume=5 |issue=9 |pages=727–738 |date=September 2018 |pmid=30097390 |pmc=6109107 |doi=10.1016/S2215-0366(18)30269-4}}</ref> Studies and meta-analyses show that amphetamine is slightly-to-modestly more effective than methylphenidate at reducing symptoms,<ref>{{cite journal |vauthors=Stuhec M, Lukić P, Locatelli I |title=Efficacy, Acceptability, and Tolerability of Lisdexamfetamine, Mixed Amphetamine Salts, Methylphenidate, and Modafinil in the Treatment of Attention-Deficit Hyperactivity Disorder in Adults: A Systematic Review and Meta-analysis |journal=[[Annals of Pharmacotherapy]] |volume=53 |issue=2 |pages=121–133 |date=February 2019 |pmid=30117329 |doi=10.1177/1060028018795703 |s2cid=52019992}}</ref><ref>{{cite journal |vauthors=Faraone SV, Biederman J, Roe C |title=Comparative efficacy of Adderall and methylphenidate in attention-deficit/hyperactivity disorder: a meta-analysis |journal=[[Journal of Clinical Psychopharmacology]] |volume=22 |issue=5 |pages=468–473 |date=October 2002 |pmid=12352269 |doi=10.1097/00004714-200210000-00005 |s2cid=19726926}}</ref> and they are more effective pharmacotherapy for ADHD than [[Alpha-adrenergic agonist#α2 agonist|α2-agonists]]<ref>{{cite journal |vauthors=Nam SH, Lim MH, Park TW |title=Stimulant Induced Movement Disorders in Attention Deficit Hyperactivity Disorder | journal = Soa--Ch'ongsonyon Chongsin Uihak = Journal of Child & Adolescent Psychiatry |volume=33 |issue=2 |pages=27–34 |date=April 2022 |pmid=35418800 |pmc=8984208 |doi=10.5765/jkacap.210034}}</ref> but methylphenidate has comparable efficacy to non-stimulants such as atomoxetine.
In a [[Cochrane (organisation)|Cochrane]] clinical synopsis, Dr Storebø and colleagues summarised their meta-review<ref>{{cite journal |vauthors=Storebø OJ, Krogh HB, Ramstad E, Moreira-Maia CR, Holmskov M, Skoog M, Nilausen TD, Magnusson FL, Zwi M, Gillies D, Rosendal S, Groth C, Rasmussen KB, Gauci D, Kirubakaran R, Forsbøl B, Simonsen E, Gluud C |title=Methylphenidate for attention-deficit/hyperactivity disorder in children and adolescents: Cochrane systematic review with meta-analyses and trial sequential analyses of randomised clinical trials |journal=[[The BMJ]] |volume=351 |article-number=h5203 |date=November 2015 |pmid=26608309 |pmc=4659414 |doi=10.1136/bmj.h5203}}</ref> on methylphenidate for ADHD in children and adolescents. The meta-analysis raised substantial doubts about the drug's efficacy relative to a placebo. This led to a strong critical reaction from the European ADHD Guidelines Group and individuals in the scientific community, who identified a number of flaws in the review.<ref>{{cite journal |vauthors=Banaschewski T, Buitelaar J, Chui CS, Coghill D, Cortese S, Simonoff E, Wong IC |title=Methylphenidate for ADHD in children and adolescents: throwing the baby out with the bathwater |journal=Evidence-Based Mental Health |volume=19 |issue=4 |pages=97–99 |date=November 2016 |pmid=27935807 |pmc=10699535 |doi=10.1136/eb-2016-102461}}</ref><ref>{{cite journal |vauthors=Hoekstra PJ, Buitelaar JK |title=Is the evidence base of methylphenidate for children and adolescents with attention-deficit/hyperactivity disorder flawed? |journal=[[European Child & Adolescent Psychiatry]] |volume=25 |issue=4 |pages=339–340 |date=April 2016 |pmid=27021055 |doi=10.1007/s00787-016-0845-2}}</ref><ref>{{cite journal |vauthors=Banaschewski T, Gerlach M, Becker K, Holtmann M, Döpfner M, Romanos M |title=Trust, but verify. The errors and misinterpretations in the Cochrane analysis by O. J. Storebo and colleagues on the efficacy and safety of methylphenidate for the treatment of children and adolescents with ADHD | journal = Zeitschrift für Kinder- und Jugendpsychiatrie und Psychotherapie |volume=44 |issue=4 |pages=307–314 |date=July 2016 |pmid=27270192 |doi=10.1024/1422-4917/a000433}}</ref><ref>{{cite journal |vauthors=Romanos M, Reif A, Banaschewski T |title=Methylphenidate for Attention-Deficit/Hyperactivity Disorder |journal=[[JAMA]] |volume=316 |issue=9 |pages=994–995 |date=September 2016 |pmid=27599342 |doi=10.1001/jama.2016.10279}}</ref><ref>{{cite journal |vauthors=Shaw P |title=Quantifying the Benefits and Risks of Methylphenidate as Treatment for Childhood Attention-Deficit/Hyperactivity Disorder |journal=[[JAMA]] |volume=315 |issue=18 |pages=1953–1955 |date=May 2016 |pmid=27163984 |doi=10.1001/jama.2016.3427}}</ref><ref>{{cite journal |vauthors=Gerlach M, Banaschewski T, Coghill D, Rohde LA, Romanos M |title=What are the benefits of methylphenidate as a treatment for children and adolescents with attention-deficit/hyperactivity disorder? |journal=Attention Deficit and Hyperactivity Disorders |volume=9 |issue=1 |pages=1–3 |date=March 2017 |pmid=28168407 |doi=10.1007/s12402-017-0220-2}}</ref> Since at least September 2021, there is a unanimous and global [[scientific consensus]] that methylphenidate is safe and highly effective for treating ADHD.<ref name="Faraone_2021" /><ref name="epa_consensus_2019" >{{cite journal |vauthors=Kooij JJ, Bijlenga D, Salerno L, Jaeschke R, Bitter I, Balázs J, Thome J, Dom G, Kasper S, Nunes Filipe C, Stes S, Mohr P, Leppämäki S, Casas M, Bobes J, Mccarthy JM, Richarte V, Kjems Philipsen A, Pehlivanidis A, Niemela A, Styr B, Semerci B, Bolea-Alamanac B, Edvinsson D, Baeyens D, Wynchank D, Sobanski E, Philipsen A, McNicholas F, Caci H, Mihailescu I, Manor I, Dobrescu I, Saito T, Krause J, Fayyad J, Ramos-Quiroga JA, Foeken K, Rad F, Adamou M, Ohlmeier M, Fitzgerald M, Gill M, Lensing M, Motavalli Mukaddes N, Brudkiewicz P, Gustafsson P, Tani P, Oswald P, Carpentier PJ, De Rossi P, Delorme R, Markovska Simoska S, Pallanti S, Young S, Bejerot S, Lehtonen T, Kustow J, Müller-Sedgwick U, Hirvikoski T, Pironti V, Ginsberg Y, Félegyházy Z, Garcia-Portilla MP, Asherson P |title=Updated European Consensus Statement on diagnosis and treatment of adult ADHD |journal=[[European Psychiatry]] |volume=56 |issue=1 |pages=14–34 |date=February 2019 |pmid=30453134 |doi=10.1016/j.eurpsy.2018.11.001 |hdl-access=free |hdl=10651/51910}}</ref> The same journal released a subsequent systematic review (2022) of extended-release methylphenidate for adults, concluding similar doubts about the certainty of evidence.<ref name="y943">{{cite journal |vauthors=Boesen K, Paludan-Müller AS, Gøtzsche PC, Jørgensen KJ |title=Extended-release methylphenidate for attention deficit hyperactivity disorder (ADHD) in adults |journal=[[The Cochrane Database of Systematic Reviews]] |volume=2022 |issue=2 |article-number=CD012857 |date=February 2022 |pmid=35201607 |pmc=8869321 |doi=10.1002/14651858.CD012857.pub2}}</ref> Other recent systematic reviews and meta-analyses, however, find certainty in the safety and high efficacy of methylphenidate for reducing ADHD symptoms,<ref name="Comparative efficacy and tolerabili"/><ref>{{cite journal |vauthors=Jaeschke RR, Sujkowska E, Sowa-Kućma M |title=Methylphenidate for attention-deficit/hyperactivity disorder in adults: a narrative review |journal=Psychopharmacology |volume=238 |issue=10 |pages=2667–2691 |date=October 2021 |pmid=34436651 |pmc=8455398 |doi=10.1007/s00213-021-05946-0}}</ref><ref>{{cite journal |vauthors=Carucci S, Balia C, Gagliano A, Lampis A, Buitelaar JK, Danckaerts M, Dittmann RW, Garas P, Hollis C, Inglis S, Konrad K, Kovshoff H, Liddle EB, McCarthy S, Nagy P, Panei P, Romaniello R, Usala T, Wong IC, Banaschewski T, Sonuga-Barke E, Coghill D, Zuddas A |title=Long term methylphenidate exposure and growth in children and adolescents with ADHD. A systematic review and meta-analysis |journal=[[Neuroscience & Biobehavioral Reviews]] |volume=120 |pages=509–525 |date=January 2021 |pmid=33080250 |doi=10.1016/j.neubiorev.2020.09.031 |url=https://discovery.dundee.ac.uk/en/publications/fe01a9b8-95ee-46bf-bd2c-e88a9d6ead38 |hdl=11584/301387 |hdl-access=free}}</ref> for alleviating the underlying executive functioning deficits,<ref>{{cite journal |vauthors=Isfandnia F, El Masri S, Radua J, Rubia K |title=The effects of chronic administration of stimulant and non-stimulant medications on executive functions in ADHD: A systematic review and meta-analysis |journal=[[Neuroscience & Biobehavioral Reviews]] |volume=162 |issue=105703 |article-number=105703 |date=July 2024 |pmid=38718988 |doi=10.1016/j.neubiorev.2024.105703 |url=https://kclpure.kcl.ac.uk/portal/en/publications/69dc26fe-1517-438e-9cd7-6788fc396dc9}}</ref> and for substantially reducing the adverse consequences of untreated ADHD with continuous treatment.<ref name="Faraone_2021" /> Clinical guidelines internationally are also consistent in approving the safety and efficacy of methylphenidate and recommending it as a first-line treatment for the disorder.<ref name="Faraone_2021" />

Safety and efficacy data have been reviewed extensively by medical regulators (e.g., the US Food and Drug Administration and the European Medicines Agency), the developers of evidence-based international guidelines (e.g., the UK National Institute for Health and Care Excellence and the American Academy of Pediatrics), and government agencies who have endorsed these guidelines (e.g., the Australian National Health and Medical Research Council). These professional groups unanimously conclude, based on the scientific evidence, that methylphenidate is safe and effective and should be considered as a first-line treatment for ADHD.<ref name="Faraone_2021" />
The likelihood of developing [[insomnia]] for ADHD patients taking stimulants has been measured at between 11 and 45 per cent for different medications,<ref name="Wynchank_2017">{{cite journal |vauthors=Wynchank D, Bijlenga D, Beekman AT, Kooij JJ, Penninx BW |title=Adult Attention-Deficit/Hyperactivity Disorder (ADHD) and Insomnia: an Update of the Literature |journal=[[Current Psychiatry Reports]] |volume=19 |issue=12 |article-number=98 |date=October 2017 |pmid=29086065 |doi=10.1007/s11920-017-0860-0 |publisher=Springer Science and Business Media LLC |quote=In varying percentages of trial participants, insomnia is a treatment-emergent adverse effect in triple-bead mixed amphetamine salts (40–45%), dasotraline (35–45%), lisdexamfetamine (10–19%), and extended-release methylphenidate (11%). |s2cid=38064951}}</ref> and may be a main reason for discontinuation. Other side effects, such as [[tic]]s, decreased appetite and weight loss, or [[emotional lability]], may also lead to discontinuation.<ref name="CNS09" /> [[Stimulant psychosis]] and [[mania]] are rare at therapeutic doses, appearing to occur in approximately 0.1% of individuals, within the first several weeks after starting amphetamine therapy.<ref name="Cochrane recreational amph psychosis">{{cite journal |vauthors=Shoptaw SJ, Kao U, Ling W |title=Treatment for amphetamine psychosis |journal=[[The Cochrane Database of Systematic Reviews]] |volume=2009 |issue=1 |article-number=CD003026 |date=January 2009 |pmid=19160215 |pmc=7004251 |doi=10.1002/14651858.CD003026.pub3 |veditors=Shoptaw SJ, Ali R |quote=A minority of individuals who use amphetamines develop full-blown psychosis requiring care at emergency departments or psychiatric hospitals. In such cases, symptoms of amphetamine psychosis commonly include paranoid and persecutory delusions as well as auditory and visual hallucinations in the presence of extreme agitation. More common (about 18%) is for frequent amphetamine users to report psychotic symptoms that are sub-clinical and that do not require high-intensity intervention&nbsp;...<br />About 5–15% of the users who develop an amphetamine psychosis fail to recover completely (Hofmann 1983)&nbsp;...<br />Findings from one trial indicate use of antipsychotic medications effectively resolves symptoms of acute amphetamine psychosis.}}</ref><ref>{{cite web |date=December 2013 |title=Adderall XR Prescribing Information |work=United States Food and Drug Administration |url=https://www.accessdata.fda.gov/drugsatfda_docs/label/2013/021303s026lbl.pdf |url-status=live |archive-url=https://web.archive.org/web/20131230233702/http://www.accessdata.fda.gov/drugsatfda_docs/label/2013/021303s026lbl.pdf |archive-date=30 December 2013 |access-date=30 December 2013 |publisher=Shire US Inc |quote=Treatment-emergent psychotic or manic symptoms, e.g., hallucinations, delusional thinking, or mania in children and adolescents without prior history of psychotic illness or mania can be caused by stimulants at usual doses.&nbsp;... In a pooled analysis of multiple short-term, placebo controlled studies, such symptoms occurred in about 0.1% (4 patients with events out of 3482 exposed to methylphenidate or amphetamine for several weeks at usual doses) of stimulant-treated patients compared to 0 in placebo-treated patients.}}</ref><ref name="pmid19171629">{{cite journal |vauthors=Mosholder AD, Gelperin K, Hammad TA, Phelan K, Johann-Liang R |title=Hallucinations and other psychotic symptoms associated with the use of attention-deficit/hyperactivity disorder drugs in children |journal=[[Pediatrics (journal)|Pediatrics]] |volume=123 |issue=2 |pages=611–616 |date=February 2009 |pmid=19171629 |doi=10.1542/peds.2008-0185 |s2cid=22391693}}</ref> The safety of these medications in pregnancy is unclear.<ref>{{cite journal |vauthors=Ashton H, Gallagher P, Moore B |title=The adult psychiatrist's dilemma: psychostimulant use in attention deficit/hyperactivity disorder |journal=[[Journal of Psychopharmacology]] |volume=20 |issue=5 |pages=602–610 |date=September 2006 |pmid=16478756 |doi=10.1177/0269881106061710 |s2cid=32073083}}</ref> Symptom improvement is not sustained if medication is ceased.<ref name="PRBM.S49114">{{cite journal |vauthors=Parker J, Wales G, Chalhoub N, Harpin V |title=The long-term outcomes of interventions for the management of attention-deficit hyperactivity disorder in children and adolescents: a systematic review of randomized controlled trials |journal=Psychology Research and Behavior Management |volume=6 |pages=87–99 |date=September 2013 |pmid=24082796 |pmc=3785407 |doi=10.2147/PRBM.S49114 |quote=Results suggest there is moderate-to-high-level evidence that combined pharmacological and behavioral interventions, and pharmacological interventions alone can be effective in managing the core ADHD symptoms and academic performance at 14 months. However, the effect size may decrease beyond this period.&nbsp;... Only one paper examining outcomes beyond 36 months met the review criteria.&nbsp;... There is high level evidence suggesting that pharmacological treatment can have a major beneficial effect on the core symptoms of ADHD (hyperactivity, inattention, and impulsivity) in approximately 80% of cases compared with placebo controls, in the short term. |doi-access=free}}</ref><ref name="May_2008"/><ref name="Castells_2018">{{cite journal |vauthors=Castells X, Blanco-Silvente L, Cunill R |title=Amphetamines for attention deficit hyperactivity disorder (ADHD) in adults |journal=[[The Cochrane Database of Systematic Reviews]] |volume=2018 |issue=8 |article-number=CD007813 |date=August 2018 |pmid=30091808 |pmc=6513464 |doi=10.1002/14651858.CD007813.pub3 |collaboration=Cochrane Developmental, Psychosocial and Learning Problems Group}}</ref>

The long-term effects of ADHD medication have yet to be fully determined,<ref name="ADHD 2015 review">{{cite journal |vauthors=Kiely B, Adesman A |title=What we do not know about ADHD... yet |journal=Current Opinion in Pediatrics |volume=27 |issue=3 |pages=395–404 |date=June 2015 |pmid=25888152 |doi=10.1097/MOP.0000000000000229 |quote=In addition, a consensus has not been reached on the optimal diagnostic criteria for ADHD. Moreover, the benefits and long-term effects of medical and complementary therapies for this disorder continue to be debated. These gaps in knowledge hinder the ability of clinicians to effectively recognise and treat ADHD. |s2cid=39004402}}</ref><ref name="pmid21519262">{{cite journal |vauthors=Hazell P |title=The challenges to demonstrating long-term effects of psychostimulant treatment for attention-deficit/hyperactivity disorder |journal=Current Opinion in Psychiatry |volume=24 |issue=4 |pages=286–290 |date=July 2011 |pmid=21519262 |doi=10.1097/YCO.0b013e32834742db |url=https://zenodo.org/record/1230054 |access-date=19 July 2019 |url-status=live |s2cid=21998152 |archive-url=https://web.archive.org/web/20200726114012/https://zenodo.org/record/1230054 |archive-date=26 July 2020}}</ref> although stimulants are generally beneficial and safe for up to two years for children and adolescents.<ref>{{cite journal |title=Attention Deficit Hyperactivity Disorder: Diagnosis and Treatment in Children and Adolescents |journal=Comparative Effectiveness Reviews |issue=203 |date=January 2018 |pmid=29558081 |url=https://www.ncbi.nlm.nih.gov/books/NBK487761/ |access-date=7 November 2021 |publisher=Agency for Healthcare Research and Quality (US) |url-status=live |place=Rockville (MD) |archive-url=https://web.archive.org/web/20220517212254/https://www.ncbi.nlm.nih.gov/books/NBK487761/ |archive-date=17 May 2022 |vauthors=Kemper AR, Maslow GR, Hill S, Namdari B, Allen Lapointe NM, Goode AP, Coeytaux RR, Befus D, Kosinski AS, Bowen SE, McBroom AJ, Lallinger KR, Sanders GD}}</ref> A 2022 meta-analysis found no statistically significant association between ADHD medications and the risk of [[cardiovascular disease]] (CVD) across age groups, although the study suggests further investigation is warranted for patients with preexisting CVD as well as long-term medication use.<ref>{{cite journal |vauthors=Zhang L, Yao H, Li L, Du Rietz E, Andell P, Garcia-Argibay M, D'Onofrio BM, Cortese S, Larsson H, Chang Z |title=Risk of Cardiovascular Diseases Associated With Medications Used in Attention-Deficit/Hyperactivity Disorder: A Systematic Review and Meta-analysis |journal=[[JAMA Network Open]] |volume=5 |issue=11 |pages=e2243597 |date=November 2022 |pmid=36416824 |pmc=9685490 |doi=10.1001/jamanetworkopen.2022.43597 |doi-access=free}}</ref> Regular monitoring has been recommended in those on long-term treatment.<ref name="pmid20571380">{{cite journal |vauthors=Kraemer M, Uekermann J, Wiltfang J, Kis B |title=Methylphenidate-induced psychosis in adult attention-deficit/hyperactivity disorder: report of 3 new cases and review of the literature |journal=Clinical Neuropharmacology |volume=33 |issue=4 |pages=204–206 |date=July 2010 |pmid=20571380 |doi=10.1097/WNF.0b013e3181e29174 |s2cid=34956456}}</ref> There are indications suggesting that stimulant therapy for children and adolescents should be stopped periodically to assess continuing need for medication, decrease possible growth delay, and reduce tolerance.<ref name="pmid21530185">{{cite journal |vauthors=van de Loo-Neus GH, Rommelse N, Buitelaar JK |title=To stop or not to stop? How long should medication treatment of attention-deficit hyperactivity disorder be extended? |journal=European Neuropsychopharmacology |volume=21 |issue=8 |pages=584–599 |date=August 2011 |pmid=21530185 |doi=10.1016/j.euroneuro.2011.03.008 |s2cid=30068561}}</ref><ref>{{cite journal |vauthors=Ibrahim K, Donyai P |title=Drug Holidays From ADHD Medication: International Experience Over the Past Four Decades |journal=[[Journal of Attention Disorders]] |volume=19 |issue=7 |pages=551–568 |date=July 2015 |pmid=25253684 |doi=10.1177/1087054714548035 |url=https://www.researchgate.net/publication/266151922 |url-status=live |s2cid=19949563 |archive-url=https://web.archive.org/web/20160630122316/https://www.researchgate.net/profile/Kinda_Ibrahim2/publication/266151922_Drug_Holidays_From_ADHD_Medication_International_Experience_Over_the_Past_Four_Decades/links/56a5ec7408ae1b651134629a.pdf |archive-date=30 June 2016}}</ref> Although potentially addictive at high doses,<ref name="NHM therapeutic stim addiction liability">{{cite book |title=Molecular Neuropharmacology: A Foundation for Clinical Neuroscience |vauthors=Malenka RC, Nestler EJ, Hyman SE |publisher=McGraw-Hill Medical |year=2009 |isbn=978-0-07-148127-4 |veditors=Sydor A, Brown RY |edition=2nd |location=New York |pages=323, 368|quote=supervised use of stimulants at therapeutic doses may decrease risk of experimentation with drugs to self-medicate symptoms. Second, untreated ADHD may lead to school failure, peer rejection, and subsequent association with deviant peer groups that encourage drug misuse.&nbsp;... amphetamines and methylphenidate are used in low doses to treat attention deficit hyperactivity disorder and in higher doses to treat narcolepsy (Chapter 12). Despite their clinical uses, these drugs are strongly reinforcing, and their long-term use at high doses is linked with potential addiction}}</ref><ref>{{Cite book |vauthors=McDonagh MS, Christensen V, Peterson K, Thakurta S |publisher=Oregon Health & Science University |title=Drug Class Review: Pharmacologic Treatments for Attention Deficit Hyperactivity Disorder: Final Report Update 3 [Internet] |chapter=Black box warnings of ADHD drugs approved by the US Food and Drug Administration |at=Appendix G: Black box warnings of ADHD drugs approved by the US Food and Drug Administration |via=United States National Library of Medicine |date=Oct 2009 |location=Portland, Oregon |url=https://www.ncbi.nlm.nih.gov/books/NBK47127/ |access-date=17 January 2014 |archive-date=8 September 2017 |archive-url=https://web.archive.org/web/20170908135126/https://www.ncbi.nlm.nih.gov/books/NBK47127/ |url-status=live}}</ref> stimulants used to treat ADHD have low potential for abuse.<ref name="Dodson_2005"/> Treatment with stimulants is either protective against substance abuse or has no effect.<ref name="Kooij_2010" />{{rp|12|quote=... the literature supports the view that stimulant treatment for ADHD either has no impact in risk for substance abuse, or may even lower the risk of substance abuse by reducing the early onset of substance abuse in adolescents.}}<ref name="ADHD 2015 review" /><ref name="NHM therapeutic stim addiction liability" />

The majority of studies on [[nicotine]] and other [[nicotinic agonist]]s as treatments for ADHD have shown favorable results; however, no nicotinic drug has been approved for ADHD treatment.<ref>{{cite journal |vauthors=Potter AS, Schaubhut G, Shipman M |title=Targeting the nicotinic cholinergic system to treat attention-deficit/hyperactivity disorder: rationale and progress to date |journal=[[CNS Drugs]] |volume=28 |issue=12 |pages=1103–1113 |date=December 2014 |pmid=25349138 |pmc=4487649 |doi=10.1007/s40263-014-0208-9}}</ref> [[Caffeine]] was formerly used as a second-line treatment for ADHD but research indicates it has no significant effects in reducing ADHD symptoms. Caffeine appears to help with alertness, arousal and reaction time but not the type of inattention implicated in ADHD (sustained attention/persistence).<ref>{{cite journal |vauthors=Perrotte G, Moreira MM, de Vargas Junior A, Teixeira Filho A, Castaldelli-Maia JM |title=Effects of Caffeine on Main Symptoms in Children with ADHD: A Systematic Review and Meta-Analysis of Randomized Trials |journal=Brain Sciences |volume=13 |issue=9 |page=1304 |date=September 2023 |pmid=37759905 |pmc=10526204 |doi=10.3390/brainsci13091304 |doi-access=free}}</ref> [[Pseudoephedrine]] and [[ephedrine]] do not affect ADHD symptoms.<ref name="Dodson_2005">{{cite journal |vauthors=Dodson WW |title=Pharmacotherapy of adult ADHD |journal=[[Journal of Clinical Psychology]] |volume=61 |issue=5 |pages=589–606 |date=May 2005 |pmid=15723384 |doi=10.1002/jclp.20122 |quote=For example, pseudoephedrine and ephedrine ... have no detectable effects on the symptoms of ADHD.}}</ref>

[[Modafinil]] has shown some efficacy in reducing the severity of ADHD in children and adolescents.<ref>{{cite journal |vauthors=Turner D |title=A review of the use of modafinil for attention-deficit hyperactivity disorder |journal=Expert Review of Neurotherapeutics |volume=6 |issue=4 |pages=455–468 |date=April 2006 |pmid=16623645 |doi=10.1586/14737175.6.4.455 |s2cid=24293088}}</ref> The only recorded side effect was increased loss of appetite.<ref>{{Cite journal |date=March 2024 |title=ADHD Diagnosis and Treatment in Children and Adolescents |url=https://effectivehealthcare.ahrq.gov/products/attention-deficit-hyperactivity-disorder/research |access-date=2025-09-20 |website=effectivehealthcare.ahrq.gov |doi=10.23970/ahrqepccer267|pmid= 38657097| vauthors = Peterson BS, Trampush J, Maglione M, Bolshakova M, Brown M, Rozelle M, Motala A, Yagyu S, Miles J, Pakdaman S, Gastelum M, Nguyen BT, Tokutomi E, Lee E, Belay JZ, Schaefer C, Coughlin B, Celosse K, Molakalapalli S, Shaw B, Sazmin T, Onyekwuluje AN, Tolentino D, Hempel S }}</ref> It may be prescribed off-label to treat ADHD.<ref>{{Cite journal |last=Flavell |first=Joshua |date=26 July 2020 |title=Modafinil-induced psychosis in a patient with attention deficit hyperactivity disorder |url=https://journals.sagepub.com/doi/10.1177/1039856220936630 |journal=Australasian Psychiatry |language=en |volume=29 |issue=3 |pages=366–367 |doi=10.1177/1039856220936630 |pmid=32713188 |issn=1039-8562 |url-access=subscription}}</ref>

====Non-stimulants====
Two non-stimulant medications, [[atomoxetine]] and [[viloxazine]], are approved by the FDA and in other countries for the treatment of ADHD.

[[Atomoxetine]], due to its lack of addiction liability, may be preferred in those who are at risk of recreational or compulsive stimulant use, although evidence is lacking to support its use over stimulants for this reason.<ref name="Kooij_2010"/>{{rp|13|The non stimulant atomoxetine may be an alternative to treatment with stimulants in substance abuse patients with ADHD, although studies showing superiority over stimulants in this difficult patient population are still lacking.}} Atomoxetine alleviates ADHD symptoms through norepinephrine reuptake and by indirectly increasing dopamine in the pre-frontal cortex,<ref name="Koda_2010"/> sharing 70–80% of the brain regions with stimulants in their produced effects.<ref name="Schulz_2012"/> Atomoxetine has been shown to significantly improve academic performance.<ref>{{cite journal |vauthors=Weiss M, Tannock R, Kratochvil C, Dunn D, Velez-Borras J, Thomason C, Tamura R, Kelsey D, Stevens L, Allen AJ |title=A randomized, placebo-controlled study of once-daily atomoxetine in the school setting in children with ADHD |journal=[[Journal of the American Academy of Child and Adolescent Psychiatry]] |volume=44 |issue=7 |pages=647–655 |date=July 2005 |pmid=15968233 |doi=10.1097/01.chi.0000163280.47221.c9}}</ref><ref>{{cite journal |vauthors=Biederman J, Wigal SB, Spencer TJ, McGough JJ, Mays DA |title=A post hoc subgroup analysis of an 18-day randomized controlled trial comparing the tolerability and efficacy of mixed amphetamine salts extended release and atomoxetine in school-age girls with attention-deficit/hyperactivity disorder |journal=[[Clinical Therapeutics]] |volume=28 |issue=2 |pages=280–293 |date=February 2006 |pmid=16678649 |doi=10.1016/j.clinthera.2006.02.008}}</ref> [[Meta-analysis|Meta-analyses]] and [[systematic review]]s have found that atomoxetine has comparable efficacy, equal tolerability and response rate (75%) to [[methylphenidate]] in children and adolescents. In adults, efficacy and discontinuation rates are equivalent.<ref name="Bushe_2016">{{cite journal |vauthors=Bushe C, Day K, Reed V, Karlsdotter K, Berggren L, Pitcher A, Televantou F, Haynes V |title=A network meta-analysis of atomoxetine and osmotic release oral system methylphenidate in the treatment of attention-deficit/hyperactivity disorder in adult patients |journal=[[Journal of Psychopharmacology]] |volume=30 |issue=5 |pages=444–458 |date=May 2016 |pmid=27005307 |doi=10.1177/0269881116636105 |s2cid=104938}}</ref><ref name="Hazell_2011">{{cite journal |vauthors=Hazell PL, Kohn MR, Dickson R, Walton RJ, Granger RE, Wyk GW |title=Core ADHD symptom improvement with atomoxetine versus methylphenidate: a direct comparison meta-analysis |journal=[[Journal of Attention Disorders]] |volume=15 |issue=8 |pages=674–683 |date=November 2011 |pmid=20837981 |doi=10.1177/1087054710379737 |s2cid=43503227}}</ref><ref name="Hanwella_2011">{{cite journal |vauthors=Hanwella R, Senanayake M, de Silva V |title=Comparative efficacy and acceptability of methylphenidate and atomoxetine in treatment of attention deficit hyperactivity disorder in children and adolescents: a meta-analysis |journal=[[BMC Psychiatry]] |volume=11 |issue=1 |article-number=176 |date=November 2011 |pmid=22074258 |pmc=3229459 |doi=10.1186/1471-244X-11-176 |doi-access=free}}</ref><ref name="Rezaei_2016">{{cite journal |vauthors=Rezaei G, Hosseini SA, Akbari Sari A, Olyaeemanesh A, Lotfi MH, Yassini M, Bidaki R, Nouri B |title=Comparative efficacy of methylphenidate and atomoxetine in the treatment of attention deficit hyperactivity disorder in children and adolescents: A systematic review and meta-analysis |journal=[[Medical Journal of the Islamic Republic of Iran]] |volume=30 |page=325 |date=10 February 2016 |pmid=27390695 |pmc=4898838}}</ref><ref>{{cite report |last1=Peterson |first1=Bradley S. |last2=Trampush |first2=Joey |last3=Maglione |first3=Margaret |last4=Bolshakova |first4=Maria |last5=Brown |first5=Morah |last6=Rozelle |first6=Mary |last7=Motala |first7=Aneesa |last8=Yagyu |first8=Sachi |last9=Miles |first9=Jeremy |last10=Pakdaman |first10=Sheila |last11=Gastelum |first11=Mario |last12=Nguyen |first12=Bich Thuy (Becky) |last13=Tokutomi |first13=Erin |last14=Lee |first14=Esther |last15=Belay |first15=Jerusalem Z. |last16=Schaefer |first16=Coleman |last17=Coughlin |first17=Benjamin |last18=Celosse |first18=Karin |last19=Molakalapalli |first19=Sreya |last20=Shaw |first20=Brittany |last21=Sazmin |first21=Tanzina |last22=Onyekwuluje |first22=Anne N. |last23=Tolentino |first23=Danica |last24=Hempel |first24=Susanne |title=ADHD Diagnosis and Treatment in Children and Adolescents |publisher=[[Agency for Healthcare Research and Quality]] |id=24-EHC003 |date=25 March 2024 |doi=10.23970/AHRQEPCCER267}}</ref>

Analyses of clinical trial data suggests that [[viloxazine]] is about as effective as atomoxetine and methylphenidate but with fewer side effects.<ref>{{cite journal |vauthors=Faraone SV, Gomeni R, Hull JT, Busse GD, Melyan Z, O'Neal W, Rubin J, Nasser A |title=Early response to SPN-812 (viloxazine extended-release) can predict efficacy outcome in pediatric subjects with ADHD: a machine learning post-hoc analysis of four randomized clinical trials |journal=[[Psychiatry Research]] |volume=296 |article-number=113664 |date=February 2021 |pmid=33418457 |doi=10.1016/j.psychres.2020.113664 |s2cid=230716405 |doi-access=free}}</ref>

[[Amantadine#Attention deficit hyperactivity disorder|Amantadine]] was shown to induce similar improvements in children treated with [[methylphenidate]], with less frequent side effects.<ref>{{cite journal |vauthors=Mohammadi MR, Kazemi MR, Zia E, Rezazadeh SA, Tabrizi M, Akhondzadeh S |date=November 2010 |title=Amantadine versus methylphenidate in children and adolescents with attention deficit/hyperactivity disorder: a randomized, double-blind trial |journal=Human Psychopharmacology |volume=25 |issue=7–8 |pages=560–565 |doi=10.1002/hup.1154 |pmid=21312290 |s2cid=30677758}}</ref> A 2021 retrospective study showed that amantadine may serve as an effective adjunct to stimulants for ADHD–related symptoms and appears to be a safer alternative to second- or third-generation antipsychotics.<ref>{{cite journal |vauthors=Morrow K, Choi S, Young K, Haidar M, Boduch C, Bourgeois JA |date=September 2021 |title=Amantadine for the treatment of childhood and adolescent psychiatric symptoms |journal=Proceedings |volume=34 |issue=5 |pages=566–570 |doi=10.1080/08998280.2021.1925827 |pmc=8366930 |pmid=34456474}}</ref>

[[Bupropion]] is also used off-label by some clinicians due to research findings. It is effective, but modestly less than atomoxetine and methylphenidate.<ref>{{cite journal |vauthors=Stuhec M, Munda B, Svab V, Locatelli I |title=Comparative efficacy and acceptability of atomoxetine, lisdexamfetamine, bupropion and methylphenidate in treatment of attention deficit hyperactivity disorder in children and adolescents: a meta-analysis with focus on bupropion |journal=[[Journal of Affective Disorders]] |volume=178 |pages=149–159 |date=June 2015 |pmid=25813457 |doi=10.1016/j.jad.2015.03.006}}</ref>

There is little evidence on the effects of medication on social behaviours.<ref name="McDonagh_20112">{{cite report |url=https://www.ncbi.nlm.nih.gov/books/NBK84419/ |title=Drug Class Review: Pharmacologic Treatments for Attention Deficit Hyperactivity Disorder |date=December 2011 |publisher=United States Library of Medicine |pmid=22420008 |archive-url=https://web.archive.org/web/20160831152630/http://www.ncbi.nlm.nih.gov/books/NBK84419/ |archive-date=31 August 2016 |url-status=live |vauthors=McDonagh MS, Peterson K, Thakurta S, Low A |series=Drug Class Reviews}}</ref> Antipsychotics may also be used to treat aggression in ADHD.<ref>{{cite journal |vauthors=Gurnani T, Ivanov I, Newcorn JH |date=February 2016 |title=Pharmacotherapy of Aggression in Child and Adolescent Psychiatric Disorders |journal=Journal of Child and Adolescent Psychopharmacology |volume=26 |issue=1 |pages=65–73 |doi=10.1089/cap.2015.0167 |pmid=26881859 |quote=Several studies (e.g., Findling et al. 2000; Armenteros et al. 2007) have shown that antipsychotics, especially second generation agents, can be effective when used together with stimulants for aggression in ADHD}}</ref>

'''Alpha-2a agonists'''

Two [[Alpha-2 agonists|alpha-2a agonists]], extended-release formulations of [[guanfacine]] and [[clonidine]], are approved by the FDA and in other countries for the treatment of ADHD (effective in children and adolescents but effectiveness has still{{when|date=October 2025}} not been shown for adults).<ref>{{cite journal |vauthors=Childress AC, Sallee FR |title=Revisiting clonidine: an innovative add-on option for attention-deficit/hyperactivity disorder |journal=Drugs of Today |volume=48 |issue=3 |pages=207–217 |date=March 2012 |pmid=22462040 |doi=10.1358/dot.2012.48.3.1750904}}</ref><ref name="Huss Chen Ludolph 2016 pp. 1–252">{{cite journal |vauthors=Huss M, Chen W, Ludolph AG |title=Guanfacine Extended Release: A New Pharmacological Treatment Option in Europe |journal=Clinical Drug Investigation |volume=36 |issue=1 |pages=1–25 |date=January 2016 |pmid=26585576 |pmc=4706844 |doi=10.1007/s40261-015-0336-0 |publisher=Springer Science and Business Media LLC}}</ref> They appear to be modestly less effective than the stimulants (amphetamine and methylphenidate) and non-stimulants (atomoxetine and viloxazine) at reducing symptoms,<ref>{{cite journal |vauthors = Biederman J, Melmed RD, Patel A, McBurnett K, Konow J, Lyne A, Scherer N |title=A randomized, double-blind, placebo-controlled study of guanfacine extended release in children and adolescents with attention-deficit/hyperactivity disorder |journal=[[Pediatrics (journal)|Pediatrics]] |volume=121 |issue=1 |pages=e73–e84 |date=January 2008 |pmid=18166547 |doi=10.1542/peds.2006-3695 |s2cid=25551406 |collaboration=SPD503 Study Group}}</ref><ref>{{cite journal |vauthors=Palumbo DR, Sallee FR, Pelham WE, Bukstein OG, Daviss WB, McDERMOTT MP |title=Clonidine for attention-deficit/hyperactivity disorder: I. Efficacy and tolerability outcomes |journal=[[Journal of the American Academy of Child and Adolescent Psychiatry]] |volume=47 |issue=2 |pages=180–188 |date=February 2008 |pmid=18182963 |doi=10.1097/chi.0b013e31815d9af7}}</ref> but can be useful alternatives or used in conjunction with a stimulant. These medications act by adjusting the alpha-2a ports on the outside of noradrenergic nerve cells in the pre-frontal executive networks, so the information (electrical signal) is less confounded by noise.<ref>{{Cite journal |title=Focus: Translational Medicine: Guanfacine for the Treatment of Cognitive Disorders: A Century of Discoveries at Yale |date=2012 |pmc=3313539 |journal=The Yale Journal of Biology and Medicine |volume=85 |issue=1 |pages=45–58 |pmid=22461743 |vauthors=Arnsten AF, Jin LE}}</ref>

====Guidelines====
[[Medical guideline|Guidelines]] on when to use medications vary by country. The United Kingdom's [[National Institute for Health and Care Excellence]] recommends use for children only in severe cases, though for adults medication is a first-line treatment.<ref name="NICE_2019">{{Cite book |author=National Institute for Health and Care Excellence |url=https://www.nice.org.uk/guidance/ng87/ |title=Attention deficit hyperactivity disorder: diagnosis and management |publisher=National Guideline Centre (UK) |year=2019 |isbn=978-1-4731-2830-9 |series=NICE Guideline, No. 87 |location=London |pages= |oclc=1126668845 |access-date=9 January 2021 |archive-url=https://web.archive.org/web/20210112035209/https://www.nice.org.uk/guidance/ng87/ |archive-date=12 January 2021 |url-status=live}}</ref> Conversely, most United States guidelines recommend medications in most age groups.<ref name="CADDRA">{{cite web |title=Canadian ADHD Practice Guidelines |url=https://www.caddra.ca/cms4/pdfs/caddraGuidelines2011Introduction.pdf |url-status=live |archive-url=https://web.archive.org/web/20210121222344/https://www.caddra.ca/cms4/pdfs/caddraGuidelines2011Introduction.pdf |archive-date=21 January 2021 |access-date=4 February 2011 |work=Canadian ADHD Resource Alliance}}</ref> Medications are especially not recommended for preschool children.<ref name="NICE_2019" /><ref name="NICE 2009" /> Underdosing of stimulants can occur, and can result in a lack of response or later loss of effectiveness.<ref>{{cite journal |vauthors=Stevens JR, Wilens TE, Stern TA |title=Using stimulants for attention-deficit/hyperactivity disorder: clinical approaches and challenges |journal=The Primary Care Companion for CNS Disorders |volume=15 |issue=2 |date=2013 |pmid=23930227 |pmc=3733520 |doi=10.4088/PCC.12f01472}}</ref> This is particularly common in adolescents and adults as approved dosing is based on school-aged children, causing some practitioners to use weight-based or benefit-based off-label dosing instead.<ref>{{cite web |vauthors=Young JL |url=http://www.medscape.org/viewarticle/734449_print |title=Individualizing Treatment for Adult ADHD: An Evidence-Based Guideline |date=20 December 2010 |website=Medscape |archive-url=https://web.archive.org/web/20220508225446/https://www.medscape.org/viewarticle/734449_print |archive-date=8 May 2022 |url-status=live |access-date=8 May 2022}}</ref><ref>{{cite web |vauthors=Biederman J |url=http://www.medscape.com/viewarticle/464377_print |title=New-Generation Long-Acting Stimulants for the Treatment of Attention-Deficit/Hyperactivity Disorder |date=21 November 2003 |website=Medscape |archive-url=https://web.archive.org/web/20220508225829/https://www.medscape.com/viewarticle/464377_print |archive-date=8 May 2022 |url-status=live |access-date=8 May 2022 |quote=As most treatment guidelines and prescribing information for stimulant medications relate to experience in school-aged children, prescribed doses for older patients are lacking. Emerging evidence for both methylphenidate and Adderall indicate that when weight-corrected daily doses, equipotent with those used in the treatment of younger patients, are used to treat adults with ADHD, these patients show a very robust clinical response consistent with that observed in pediatric studies. These data suggest that older patients may require a more aggressive approach in terms of dosing, based on the same target dosage ranges that have already been established&nbsp;– for methylphenidate, 1–1.5–2 mg/kg/day, and for D,L-amphetamine, 0.5–0.75–1 mg/kg/day.... <br />In particular, adolescents and adults are vulnerable to underdosing, and are thus at potential risk of failing to receive adequate dosage levels. As with all therapeutic agents, the efficacy and safety of stimulant medications should always guide prescribing behavior: careful dosage titration of the selected stimulant product should help to ensure that each patient with ADHD receives an adequate dose, so that the clinical benefits of therapy can be fully attained.}}</ref><ref>{{cite journal |vauthors=Kessler S |title=Drug therapy in attention-deficit hyperactivity disorder |journal=[[Southern Medical Journal]] |volume=89 |issue=1 |pages=33–38 |date=January 1996 |pmid=8545689 |doi=10.1097/00007611-199601000-00005 |s2cid=12798818}}</ref>

=== Exercise ===
Exercise does not reduce the symptoms of ADHD.<ref name="Faraone_2021" /> The conclusion by the International Consensus Statement is based on two meta-analyses: one of 10 studies with 300 children and the other of 15 studies and 668 participants, which showed that exercise yields no statistically significant reductions on ADHD symptoms. A 2024 systematic review and meta analysis commissioned by the Patient-Centered Outcomes Research Institute (PCORI) identified seven studies on the effectiveness of physical exercise for treating ADHD symptoms.<ref name="Peterson_2024a" /> The type and amount of exercise varied widely across studies from martial arts interventions to treadmill training, to table tennis or aerobic exercise. Effects reported were not replicated, causing the authors to conclude that there is insufficient evidence that exercise intervention is an effective form of treatment for ADHD symptoms.<ref name="Peterson_2024a" />

=== Diet ===
Dietary modifications are not recommended {{as of|2019|lc=y}} by the [[American Academy of Pediatrics]], the [[National Institute for Health and Care Excellence]], or the [[Agency for Healthcare Research and Quality]] due to insufficient evidence.<ref name="APP2019">{{cite journal |vauthors=Wolraich ML, Hagan JF, Allan C, Chan E, Davison D, Earls M, Evans SW, Flinn SK, Froehlich T, Frost J, Holbrook JR, Lehmann CU, Lessin HR, Okechukwu K, Pierce KL, Winner JD, Zurhellen W |title=Clinical Practice Guideline for the Diagnosis, Evaluation, and Treatment of Attention-Deficit/Hyperactivity Disorder in Children and Adolescents |journal=[[Pediatrics (journal)|Pediatrics]] |volume=144 |issue=4 |article-number=e20192528 |date=October 2019 |pmid=31570648 |pmc=7067282 |doi=10.1542/peds.2019-2528}}</ref><ref name="NICE_2019" />
A 2013 meta-analysis found less than a third of children with ADHD see some improvement in symptoms with [[free fatty acid]] supplementation or decreased consumption of artificial food colouring.<ref name="Sonu_2013">{{cite journal |vauthors=Sonuga-Barke EJ, Brandeis D, Cortese S, Daley D, Ferrin M, Holtmann M, Stevenson J, Danckaerts M, van der Oord S, Döpfner M, Dittmann RW, Simonoff E, Zuddas A, Banaschewski T, Buitelaar J, Coghill D, Hollis C, Konofal E, Lecendreux M, Wong IC, Sergeant J |title=Nonpharmacological interventions for ADHD: systematic review and meta-analyses of randomized controlled trials of dietary and psychological treatments |journal=[[The American Journal of Psychiatry]] |volume=170 |issue=3 |pages=275–289 |date=March 2013 |pmid=23360949 |doi=10.1176/appi.ajp.2012.12070991 |lccn=22024537 |quote=Free fatty acid supplementation and artificial food colour exclusions appear to have beneficial effects on ADHD symptoms, although the effect of the former are small and those of the latter may be limited to ADHD patients with food sensitivities... |s2cid=434310 |oclc=1480183 |eissn=1535-7228}}</ref> These benefits may be limited to children with food sensitivities or those who are simultaneously being treated with ADHD medications.<ref name="Sonu_2013" /> This review also found that evidence does not support removing other foods from the diet to treat ADHD.<ref name="Sonu_2013" /> A 2014 review found that an [[elimination diet]] results in a small overall benefit in a minority of children, such as those with allergies.<ref name="Nigg_2014">{{cite journal |vauthors=Nigg JT, Holton K |title=Restriction and elimination diets in ADHD treatment |journal=Child and Adolescent Psychiatric Clinics of North America |volume=23 |issue=4 |pages=937–953 |date=October 2014 |pmid=25220094 |pmc=4322780 |doi=10.1016/j.chc.2014.05.010 |type=Review |quote=an elimination diet produces a small aggregate effect but may have greater benefit among some children. Very few studies enable proper evaluation of the likelihood of response in children with ADHD who are not already preselected based on prior diet response.}}</ref> A 2016 review stated that the use of a [[gluten-free diet]] as standard ADHD treatment is not advised.<ref name="pmid26825336">{{cite journal |vauthors=Ertürk E, Wouters S, Imeraj L, Lampo A |date=August 2020 |title=Association of ADHD and Celiac Disease: What Is the Evidence? A Systematic Review of the Literature |journal=[[Journal of Attention Disorders]] |type=Review |volume=24 |issue=10 |pages=1371–1376 |doi=10.1177/1087054715611493 |pmid=26825336 |s2cid=33989148 |quote=Up till now, there is no conclusive evidence for a relationship between ADHD and {{abbr|CD|celiac disease}}. Therefore, it is not advised to perform routine screening of CD when assessing ADHD (and vice versa) or to implement {{abbr|GFD|gluten-free diet}} as a standard treatment in ADHD. Nevertheless, the possibility of untreated CD predisposing to ADHD-like behavior should be kept in mind.&nbsp;... It is possible that in untreated patients with CD, neurologic symptoms such as chronic fatigue, inattention, pain, and headache could predispose patients to ADHD-like behavior (mainly symptoms of inattentive type), which may be alleviated after GFD treatment.}}</ref> A 2017 review showed that a few-foods elimination diet may help children too young to be medicated or not responding to medication, while free fatty acid supplementation or decreased eating of artificial food colouring as standard ADHD treatment is not advised.<ref name="Pelsser_2017">{{cite journal |vauthors=Pelsser LM, Frankena K, Toorman J, Rodrigues Pereira R |title=Diet and ADHD, Reviewing the Evidence: A Systematic Review of Meta-Analyses of Double-Blind Placebo-Controlled Trials Evaluating the Efficacy of Diet Interventions on the Behavior of Children with ADHD |journal=[[PLOS ONE]] |volume=12 |issue=1 |article-number=e0169277 |date=January 2017 |pmid=28121994 |pmc=5266211 |doi=10.1371/journal.pone.0169277 |type=[[Systematic Review]] |doi-access=free |bibcode=2017PLoSO..1269277P}}</ref>

Chronic deficiencies of iron, magnesium and iodine may have a negative impact on ADHD symptoms.<ref name="pmid22928358">{{cite journal |vauthors=Konikowska K, Regulska-Ilow B, Rózańska D |title=The influence of components of diet on the symptoms of ADHD in children |journal=Roczniki Panstwowego Zakladu Higieny |volume=63 |issue=2 |pages=127–134 |year=2012 |pmid=22928358}}</ref> There is a small amount of evidence that lower tissue zinc levels may be associated with ADHD.<ref name="pmid16190793">{{cite journal |vauthors=Arnold LE, DiSilvestro RA |title=Zinc in attention-deficit/hyperactivity disorder |journal=[[Journal of Child and Adolescent Psychopharmacology]] |volume=15 |issue=4 |pages=619–627 |date=August 2005 |pmid=16190793 |doi=10.1089/cap.2005.15.619 |hdl-access=free |hdl=1811/51593}}</ref> In the absence of a demonstrated [[zinc deficiency]] (which is rare outside of developing countries), zinc supplementation is not recommended as treatment for ADHD.<ref name="pmid25220092">{{cite journal |vauthors=Bloch MH, Mulqueen J |title=Nutritional supplements for the treatment of ADHD |journal=Child and Adolescent Psychiatric Clinics of North America |volume=23 |issue=4 |pages=883–897 |date=October 2014 |pmid=25220092 |pmc=4170184 |doi=10.1016/j.chc.2014.05.002}}</ref> However, zinc supplementation may reduce the minimum [[Effective dose (pharmacology)|effective dose]] of amphetamine when it is used with amphetamine for the treatment of ADHD.<ref name="Kraus_2008">{{cite journal |vauthors=Krause J |title=SPECT and PET of the dopamine transporter in attention-deficit/hyperactivity disorder |journal=Expert Review of Neurotherapeutics |volume=8 |issue=4 |pages=611–625 |date=April 2008 |pmid=18416663 |doi=10.1586/14737175.8.4.611 |quote=Zinc binds at&nbsp;... extracellular sites of the DAT, serving as a DAT inhibitor. In this context, controlled double-blind studies in children are of interest, which showed positive effects of zinc [supplementation] on symptoms of ADHD. It should be stated that at this time [supplementation] with zinc is not integrated in any ADHD treatment algorithm. |s2cid=24589993}}</ref>

==Prognosis==
About 30–50% of people diagnosed in childhood continue to have [[Adult attention deficit hyperactivity disorder|ADHD in adulthood]], with 2.58% of adults estimated to have ADHD which began in childhood.<ref name="Song_2021" /><ref name="Ginsberg_2014">{{cite journal |vauthors=Ginsberg Y, Quintero J, Anand E, Casillas M, Upadhyaya HP |title=Underdiagnosis of attention-deficit/hyperactivity disorder in adult patients: a review of the literature |journal=The Primary Care Companion for CNS Disorders |volume=16 |issue=3 |year=2014 |pmid=25317367 |pmc=4195639 |doi=10.4088/PCC.13r01600 |quote=Reports indicate that ADHD affects 2.5%–5% of adults in the general population,<sup>5–8</sup> compared with 5%–7% of children.<sup>9,10</sup>&nbsp;... However, fewer than 20% of adults with ADHD are currently diagnosed and/or treated by psychiatrists.<sup>7,15,16</sup>}}</ref>{{Text-source inline|date=August 2022}} Children with ADHD have worse educational outcomes<ref name="fleming_et_al_2017" /> and a higher risk of unintentional injuries.<ref name="Ruiz-Goikoetxea_2017" /> In adults, hyperactivity is often replaced by inner [[Psychomotor agitation|restlessness]], and adults affected are likely to develop [[coping]] mechanisms as they mature, thus compensating to some extent for their previous symptoms.<ref name="Coghill_2017" /><ref name="Art.218" />

The negative impacts of ADHD symptoms contribute to poor health-related quality of life that may be further exacerbated by, or may increase the risk of, other psychiatric conditions such as anxiety and depression.<ref name="Coghill_2017" /><ref>{{cite journal |vauthors=Lee YC, Yang HJ, Chen VC, Lee WT, Teng MJ, Lin CH, Gossop M |title=Meta-analysis of quality of life in children and adolescents with ADHD: By both parent proxy-report and child self-report using PedsQL™ |journal=Research in Developmental Disabilities |volume=51-52 |pages=160–172 |date=1 April 2016 |pmid=26829402 |doi=10.1016/j.ridd.2015.11.009}}</ref> Individuals with ADHD may also face misconceptions and stigma.<ref name="Faraone_2021" /> A number of recent studies have found that ADHD is associated with a significant reduction in average life expectancy.<ref name="Barkley & Fischer">{{cite journal |vauthors=Barkley RA, Fischer M |title=Hyperactive Child Syndrome and Estimated Life Expectancy at Young Adult Follow-Up: The Role of ADHD Persistence and Other Potential Predictors |journal=[[Journal of Attention Disorders]] |volume=23 |issue=9 |pages = 907–923 |date=July 2019 |pmid=30526189 |doi=10.1177/1087054718816164 |s2cid=54472439}}</ref><ref name="Adverse_2022" /><ref>{{cite journal |last1=O'Nions |first1=Elizabeth |last2=El Baou |first2=Céline |last3=John |first3=Amber |last4=Lewer |first4=Dan |last5=Mandy |first5=Will |last6=McKechnie |first6=Douglas G.J. |last7=Petersen |first7=Irene |last8=Stott |first8=Josh |title=Life expectancy and years of life lost for adults with diagnosed ADHD in the UK: matched cohort study |journal=The British Journal of Psychiatry |date=23 January 2025 |volume=226 |issue=5 |pages=261–268 |doi=10.1192/bjp.2024.199 |pmid=39844532 |pmc=7617439 }}</ref> A US study found rates of smoking among those with ADHD are higher than in the general population.<ref>{{cite journal |vauthors=McClernon FJ, Kollins SH |title=ADHD and smoking: from genes to brain to behavior |journal=[[Annals of the New York Academy of Sciences]] |volume=1141 |issue=1 |pages=131–147 |date=October 2008 |pmid=18991955 |pmc=2758663 |doi=10.1196/annals.1441.016 |bibcode=2008NYASA1141..131M}}</ref> Positive effects of medication on functional impairment and quality of life (e.g. reduced risk of accidents) have been found across multiple domains.<ref>{{cite journal |vauthors=Faraone SV, Asherson P, Banaschewski T, Biederman J, Buitelaar JK, Ramos-Quiroga JA, Rohde LA, Sonuga-Barke EJ, Tannock R, Franke B |title=Attention-deficit/hyperactivity disorder |journal=[[Nature Reviews Disease Primers]] |volume=1 |article-number=15020 |date=August 2015 |pmid=27189265 |doi=10.1038/nrdp.2015.20 |s2cid=7171541 |citeseerx=10.1.1.497.1346 |type=Review}}</ref>

Individuals with ADHD are significantly overrepresented in prison populations. Although there is no generally accepted estimate of ADHD prevalence among inmates, a 2015 meta-analysis estimated a prevalence of 25.5%, and a larger 2018 meta-analysis estimated the frequency to be 26.2%.<ref>{{cite journal |vauthors=Baggio S, Fructuoso A, Guimaraes M, Fois E, Golay D, Heller P, Perroud N, Aubry C, Young S, Delessert D, Gétaz L, Tran NT, Wolff H |title=Prevalence of Attention Deficit Hyperactivity Disorder in Detention Settings: A Systematic Review and Meta-Analysis |journal=[[Frontiers in Psychiatry]] |volume=9 |article-number=331 |date=2 August 2018 |pmid=30116206 |pmc=6084240 |doi=10.3389/fpsyt.2018.00331 |doi-access=free}}</ref>

New research in 2025 indicates that adults diagnosed with ADHD may have a shorter lifespan compared to those without the condition.<ref>{{Cite news |last=Barry |first=Ellen |date=23 January 2025 |title=People With A.D.H.D. Are Likely to Die Significantly Earlier Than Their Peers, Study Finds |url=https://www.nytimes.com/2025/01/23/health/adhd-life-expectancy.html |access-date=25 January 2025 |work=[[The New York Times]] |language=en-US |issn=0362-4331}}</ref> The study revealed that, on average, men with ADHD lived seven years less than men without ADHD, while women with ADHD had a lifespan nine years shorter than their peers.<ref>{{Cite journal |last1=O'Nions |first1=Elizabeth |last2=Baou |first2=Céline El |last3=John |first3=Amber |last4=Lewer |first4=Dan |last5=Mandy |first5=Will |last6=McKechnie |first6=Douglas G. J. |last7=Petersen |first7=Irene |last8=Stott |first8=Josh |date=23 January 2025 |title=Life expectancy and years of life lost for adults with diagnosed ADHD in the UK: matched cohort study |journal=[[British Journal of Psychiatry]] |volume=226 |issue=5 |language=en |pages=261–268 |doi=10.1192/bjp.2024.199 |pmid=39844532 |pmc=7617439 |issn=0007-1250}}</ref> Although the study did not pinpoint exact causes of death, it highlighted that individuals with ADHD were more likely to engage in [[smoking]], [[Alcohol abuse|alcohol misuse]], and face other health challenges such as [[Depression (mood)|depression]], self-harm, or [[personality disorder]]s.<ref>{{Cite news |last=Godoy |first=Maria |date=23 January 2025 |title=Adults with ADHD live shorter lives than those without a diagnosis, a new study finds |url=https://www.npr.org/sections/shots-health-news/2025/01/23/nx-s1-5272801/adhd-research-shorter-life-expectancy-attention-deficit-hyperactivity-disorder |access-date=25 January 2025 |work=[[NPR]] |language=en}}</ref>

==Epidemiology==
{{Main|Epidemiology of attention deficit hyperactive disorder}}

[[File:Map-Ever-Diagnosed-2011-550px.jpg|thumb|upright=1.35|Percentages of people from ages 4 to 17 ever diagnosed in the US as of 2011<ref>{{cite web |title=State-based Prevalence Data of Parent Reported ADHD |url=https://www.cdc.gov/ncbddd/adhd/prevalence.html |website=Centers for Disease Control and Prevention |access-date=31 March 2020 |date=13 February 2017 |archive-date=30 March 2019 |archive-url=https://web.archive.org/web/20190330123802/https://www.cdc.gov/ncbddd/adhd/prevalence.html |url-status=live}}</ref>]]
ADHD is estimated to affect about&nbsp;6–7% of people aged 18 and under when diagnosed via the DSM-IV criteria.<ref name="pmid22976615"/> When diagnosed via the ICD-10 criteria, rates in this age group are estimated around&nbsp;1–2%.<ref name="Cowen_2012">{{cite book |vauthors=Cowen P, Harrison P, Burns T |url=https://books.google.com/books?id=O3sSd-OAdP0C |title=Shorter Oxford Textbook of Psychiatry |publisher=[[Oxford University Press]] |year=2012 |isbn=978-0-19-960561-3 |edition=6th |pages=[https://books.google.com/books?id=O3sSd-OAdP0C&pg=PA546 546] |chapter=Drugs and other physical treatments |chapter-url=https://books.google.com/books?id=O3sSd-OAdP0C&pg=PA507}}</ref> Rates are similar between countries and differences in rates depend mostly on how it is diagnosed.<ref name="Jones_2011">{{cite book |title=Textbook of Psychiatric Epidemiology |vauthors=Faraone SV |publisher=[[John Wiley & Sons]] |year=2011 |isbn=978-0-470-97740-8 |veditors=Tsuang MT, Tohen M, Jones P |edition=3rd |page=450 |chapter=Ch. 25: Epidemiology of Attention Deficit Hyperactivity Disorder |access-date=1 February 2016 |chapter-url=https://books.google.com/books?id=fOc4pdXe43EC&pg=PA450 |archive-url=https://web.archive.org/web/20201222193454/https://books.google.com/books?id=fOc4pdXe43EC&pg=PA450 |archive-date=22 December 2020 |url-status=live}}</ref> Children in North America appear to have a higher rate of ADHD than children in Africa and the Middle East; this is believed to be due to differing methods of diagnosis rather than a difference in underlying frequency. (The same publication which describes this difference also notes that the difference may be rooted in the available studies from these respective regions, as far more studies were from North America than from Africa and the Middle East.)<ref name="Polanczyk_2007">{{cite journal |vauthors=Polanczyk G, de Lima MS, Horta BL, Biederman J, Rohde LA |title=The worldwide prevalence of ADHD: a systematic review and metaregression analysis |journal=[[The American Journal of Psychiatry]] |volume=164 |issue=6 |pages=942–948 |date=June 2007 |pmid=17541055 |doi=10.1176/appi.ajp.164.6.942 |lccn=22024537 |doi-access=free |oclc=1480183 |eissn=1535-7228}}</ref><!--From recollection, this article may be better summarised as "kids in NA have a higher rate of DIAGNOSIS". It may be a subtle difference but it's very important.--> {{As of|2019|post=,}} it was estimated to affect 84.7 million people globally.<ref name=GBD2019>{{Cite journal |author=[[Institute for Health Metrics and Evaluation]] |date=17 October 2020 |title=Global Burden of Disease Study 2019: Attention-deficit/hyperactivity disorder—Level 3 cause |url=https://www.thelancet.com/pb-assets/Lancet/gbd/summaries/diseases/adhd.pdf |journal=[[The Lancet]] |volume=396 |issue=10258 |via= |access-date=7 January 2021 |archive-date=7 January 2021 |archive-url=https://web.archive.org/web/20210107135215/https://www.thelancet.com/pb-assets/Lancet/gbd/summaries/diseases/adhd.pdf |url-status=live |at=Table 1}}. Both DSM-IV-TR and ICD-10 criteria were used.</ref>

ADHD is diagnosed approximately twice as often in boys as in girls,<ref name="DSM5TR" /><ref name="pmid22976615">{{cite journal |vauthors=Willcutt EG |title=The prevalence of DSM-IV attention-deficit/hyperactivity disorder: a meta-analytic review |journal=Neurotherapeutics |volume=9 |issue=3 |pages=490–499 |date=July 2012 |pmid=22976615 |pmc=3441936 |doi=10.1007/s13311-012-0135-8}}</ref> and 1.6 times more often in men than in women,<ref name="DSM5TR" /> although the disorder is overlooked in girls or diagnosed in later life because their symptoms sometimes differ from diagnostic criteria.{{refn|<ref>{{cite journal |vauthors=Young S, Adamo N, Ásgeirsdóttir BB, Branney P, Beckett M, Colley W, Cubbin S, Deeley Q, Farrag E, Gudjonsson G, Hill P, Hollingdale J, Kilic O, Lloyd T, Mason P, Paliokosta E, Perecherla S, Sedgwick J, Skirrow C, Tierney K, van Rensburg K, Woodhouse E |title=Females with ADHD: An expert consensus statement taking a lifespan approach providing guidance for the identification and treatment of attention-deficit/ hyperactivity disorder in girls and women |journal=[[BMC Psychiatry]] |volume=20 |issue=1 |article-number=404 |date=August 2020 |pmid=32787804 |pmc=7422602 |doi=10.1186/s12888-020-02707-9 |doi-access=free}}</ref><ref>{{cite journal |vauthors=Crawford N |date=February 2003 |title=ADHD: a women's issue |journal=Monitor on Psychology |volume=34 |issue=2 |page=28 |url=http://www.apa.org/monitor/feb03/adhd.aspx |url-status=live |archive-url=https://web.archive.org/web/20170409110923/http://www.apa.org/monitor/feb03/adhd.aspx |archive-date=9 April 2017}}</ref><ref name="pmid19393378">{{cite journal |vauthors=Emond V, Joyal C, Poissant H |title=[Structural and functional neuroanatomy of attention-deficit hyperactivity disorder (ADHD)] |language=fr |journal=L'Encephale |volume=35 |issue=2 |pages=107–114 |date=April 2009 |pmid=19393378 |doi=10.1016/j.encep.2008.01.005 |trans-title=Structural and functional neuroanatomy of attention-deficit hyperactivity disorder (ADHD)}}</ref><ref name="Singh_2008">{{cite journal |vauthors=Singh I |title=Beyond polemics: science and ethics of ADHD |journal=[[Nature Reviews Neuroscience]] |volume=9 |issue=12 |pages=957–964 |date=December 2008 |pmid=19020513 |doi=10.1038/nrn2514 |s2cid=205504587}}</ref>}}<ref>{{cite journal |vauthors=Staller J, Faraone SV |title=Attention-deficit hyperactivity disorder in girls: epidemiology and management |journal=[[CNS Drugs]] |volume=20 |issue=2 |pages=107–123 |year=2006 |pmid=16478287 |doi=10.2165/00023210-200620020-00003 |s2cid=25835322}}</ref> In 2014, [[Keith Conners]], one of the early advocates for recognition of the disorder, spoke out against overdiagnosis in a ''[[New York Times]]'' article.<ref name="NYT2013">{{cite news |vauthors=Schwarz A |title=The Selling of Attention Deficit Disorder |url=https://www.nytimes.com/2013/12/15/health/the-selling-of-attention-deficit-disorder.html |access-date=26 February 2015 |newspaper=The New York Times |date=14 December 2013 |url-status=live |archive-url=https://web.archive.org/web/20150301054334/http://www.nytimes.com/2013/12/15/health/the-selling-of-attention-deficit-disorder.html |archive-date=1 March 2015}}</ref> In contrast, a 2014 peer-reviewed medical literature review indicated that ADHD is underdiagnosed in adults.<ref name="Ginsberg_2014" />

Studies from multiple countries have reported that children born closer to the start of the school year are more frequently diagnosed with and medicated for ADHD than their older classmates.<ref>{{cite journal |vauthors=Whitely M, Raven M, Timimi S, Jureidini J, Phillimore J, Leo J, Moncrieff J, Landman P |title=Attention deficit hyperactivity disorder late birthdate effect common in both high and low prescribing international jurisdictions: a systematic review |journal=[[Journal of Child Psychology and Psychiatry|Journal of Child Psychology and Psychiatry, and Allied Disciplines]] |volume=60 |issue=4 |pages=380–391 |date=April 2019 |pmid=30317644 |pmc=7379308 |doi=10.1111/jcpp.12991}}</ref> Boys who were born in December where the school age cut-off was 31 December were shown to be 30% more likely to be diagnosed and 41% more likely to be treated than those born in January. Girls born in December had a diagnosis and treatment percentage increase of 70% and 77% respectively compared to those born in January. Children who were born at the last three days of a calendar year were reported to have significantly higher levels of diagnosis and treatment for ADHD than children born at the first three days of a calendar year. The studies suggest that ADHD diagnosis is prone to subjective analysis.<ref name="Ford-Jones_2015" />

Rates of diagnosis and treatment have increased in both the United Kingdom and the United States since the 1970s. Prior to 1970, it was rare for children to be diagnosed with ADHD, while in the 1970s rates were about 1%.<ref>{{cite periodical |vauthors=Connor DF |date=2011 |title=Problems of overdiagnosis and overprescribing in ADHD: are they legitimate? |url=https://www.psychiatrictimes.com/view/problems-overdiagnosis-and-overprescribing-adhd |url-status=live |archive-url=https://web.archive.org/web/20210812122049/https://www.psychiatrictimes.com/view/problems-overdiagnosis-and-overprescribing-adhd |archive-date=12 August 2021 |magazine=Psychiatric Times |volume=28 |issue=8 |page=14}}</ref> This is believed to be primarily due to changes in how the condition is diagnosed<ref name="CDCTime2013" /> and how readily people are willing to treat it with medications rather than a true change in incidence.<ref name="Cowen_2012" /> With widely differing rates of diagnosis across countries, states within countries, races, and ethnicities, some suspect factors other than symptoms of ADHD are playing a role in diagnosis, such as cultural norms.<ref name="Elder-2010">{{cite journal |vauthors=Elder TE |title=The importance of relative standards in ADHD diagnoses: evidence based on exact birth dates |journal=[[Journal of Health Economics]] |volume=29 |issue=5 |pages=641–656 |date=September 2010 |pmid=20638739 |pmc=2933294 |doi=10.1016/j.jhealeco.2010.06.003}}</ref><ref name="Ford-Jones_2015">{{cite journal |vauthors=Ford-Jones PC |title=Misdiagnosis of attention deficit hyperactivity disorder: 'Normal behaviour' and relative maturity |journal=[[Paediatrics & Child Health]] |volume=20 |issue=4 |pages=200–202 |date=May 2015 |pmid=26038639 |pmc=4443828 |doi=10.1093/pch/20.4.200}}</ref>

Despite showing a higher frequency of symptoms associated with ADHD, [[people of colour|non-White]] children in the US are less likely than [[White American|White]] children to be diagnosed or treated for ADHD, a finding that is often explained by bias among health professionals, as well as parents who may be reluctant to acknowledge that their child has ADHD.<ref>{{cite journal |vauthors=Coker TR, Elliott MN, Toomey SL, Schwebel DC, Cuccaro P, Tortolero Emery S, Davies SL, Visser SN, Schuster MA |title=Racial and Ethnic Disparities in ADHD Diagnosis and Treatment |journal=[[Pediatrics (journal)|Pediatrics]] |volume=138 |issue=3 |pages=e20160407 |date=September 2016 |pmid=27553219 |pmc=5684883 |doi=10.1542/peds.2016-0407 |quote=There are various improvements in care that may help in closing this gap in diagnosis and treatment. These include actively and universally eliciting parental concerns about child behavior and academic performance (at home and school) at well-visits,32,33 providing care that is culturally relevant in families' preferred languages,34 and linking with community resources to provide mental health education, guidance, and services to families (eg, parent training courses for parents of children with ADHD).35–39 Pediatric clinicians also may need to consider universal behavioral health screening tools for children to improve diagnostic capabilities and recognise when a child has ADHD symptoms, even if the problem is not recognised by the parent. Because the rates of diagnosis and treatment are rising in the general population of US children, a significant need remains to identify and treat African-American and Latino children who have ADHD and avoid a widening of these disparities.}}</ref> Crosscultural differences in diagnosis of ADHD can also be attributed to the long-lasting effects of harmful, racially targeted medical practices. Medical pseudosciences, particularly those that targeted Black populations during the period of slavery in the US, lead to a distrust of medical practices within certain communities. The combination of ADHD symptoms often being regarded as misbehaviour rather than as a psychiatric condition, and the use of drugs to regulate ADHD, result in a hesitancy to trust a diagnosis of ADHD. Cases of misdiagnosis in ADHD can also occur due to stereotyping of people of colour. Due to ADHD's subjectively determined symptoms, medical professionals may diagnose individuals based on stereotyped behaviour or misdiagnose due to cultural differences in symptom presentation.<ref name="Slobodin_2020">{{cite journal |vauthors=Slobodin O, Masalha R |title=Challenges in ADHD care for ethnic minority children: A review of the current literature |journal=Transcultural Psychiatry |volume=57 |issue=3 |pages=468–483 |date=June 2020 |pmid=32233772 |doi=10.1177/1363461520902885 |s2cid=214768588}}</ref>

A 2024 study in [[Centers for Disease Control and Prevention|CDC]]'s [[Morbidity and Mortality Weekly Report]] reports around 15.5 million U.S. adults have attention-deficit hyperactivity disorder, with many facing challenges in accessing treatment.<ref>{{Cite journal |last=Staley |first=Brooke S. |date=2024 |title=Attention-Deficit/Hyperactivity Disorder Diagnosis, Treatment, and Telehealth Use in Adults — National Center for Health Statistics Rapid Surveys System, United States, October–November 2023 |url=https://www.cdc.gov/mmwr/volumes/73/wr/mm7340a1.htm?s_cid=mm7340a1_w |journal=MMWR. Morbidity and Mortality Weekly Report |language=en-us |volume=73 |issue=40 |pages=890–895 |doi=10.15585/mmwr.mm7340a1 |pmid=39388378 |pmc=11466376 |issn=0149-2195}}</ref> One-third of diagnosed individuals had received a prescription for a stimulant drug in the past year but nearly three-quarters of them reported difficulties filling the prescription due to medication shortages.<ref>{{Cite news |last=Singh |first=Puyaan |date=10 October 2024 |title=More than 15 million US adults have ADHD, new study estimates |url=https://www.reuters.com/business/healthcare-pharmaceuticals/more-than-15-million-us-adults-have-adhd-new-study-estimates-2024-10-10/ |work=[[Reuters]]}}</ref>

==History==
[[File:CDCHisGraph.png|thumb|upright=1.35|Timeline of ADHD diagnostic criteria, prevalence, and treatment]]
{{Main|History of attention deficit hyperactivity disorder}}

ADHD was officially known as '''attention deficit disorder''' ('''ADD''') from 1980 to 1987; prior to the 1980s, it was known as '''hyperkinetic reaction of childhood'''. Symptoms similar to those of ADHD have been described in medical literature dating back to the 18th century. Sir [[Alexander Crichton]] describes "mental restlessness" in his book ''An inquiry into the nature and origin of mental derangement'' written in 1798.<ref>{{cite journal |date=May 2001 |title=An early description of ADHD (inattentive subtype): Dr Alexander Crichton and 'Mental restlessness' (1798) |volume=6 |issue=2 |pages=66–73 |journal=[[Child and Adolescent Mental Health]] |doi=10.1111/1475-3588.00324 |vauthors=Palmer ED, Finger S}}</ref><ref>{{cite book |vauthors=Crichton A |title=An inquiry into the nature and origin of mental derangement: comprehending a concise system of the physiology and pathology of the human mind and a history of the passions and their effects |url=https://books.google.com/books?id=OMAtAAAAYAAJ |orig-date=1798 |date=1976 |publisher=AMS Press |location=United Kingdom |isbn=978-0-404-08212-3 |page=271 |access-date=17 January 2014 |archive-date=3 April 2019 |archive-url=https://web.archive.org/web/20190403124410/https://books.google.com/books?id=OMATAAAAYAAJ |url-status=live}}</ref> He made observations about children showing signs of being inattentive and having the "fidgets". The first clear description of ADHD is credited to [[George Still]] in 1902 during a series of lectures he gave to the Royal College of Physicians of London.<ref>{{Cite journal |vauthors=Still G |date=1902 |title=Some Abnormal Psychical Conditions in Children: The Goulstonian Lectures |volume=159 |doi=10.1016/s0140-6736(01)74984-7 |journal=[[The Lancet]] |pages=1008–1012}}</ref><ref name="CDCTime2013">{{cite web |title=ADHD Throughout the Years |url=https://www.cdc.gov/ncbddd/adhd/documents/timeline.pdf |publisher=Center For Disease Control and Prevention |access-date=2 August 2013 |url-status=live |archive-url=https://web.archive.org/web/20130807202545/http://www.cdc.gov/ncbddd/adhd/documents/timeline.pdf |archive-date=7 August 2013}}</ref>

The terminology used to describe the condition has changed over time and has included: {{Visible anchor|Minimal brain dysfunction|text=''minimal brain dysfunction'' in the DSM-I (1952, also called ''minimal cerebral dysfunction'')}}, ''hyperkinetic reaction of childhood'' in the DSM-II (1968), and ''attention-deficit disorder with or without hyperactivity'' in the DSM-III (1980).<ref name="CDCTime2013" /> In 1987, the symptoms of inattention, impulsivity, and hyperactivity were collectively combined to define the new diagnosis of ADHD,<ref>{{Cite journal |last1=Lange |first1=Klaus W. |last2=Reichl |first2=Susanne |last3=Lange |first3=Katharina M. |last4=Tucha |first4=Lara |last5=Tucha |first5=Oliver |date=December 2010 |title=The history of attention deficit hyperactivity disorder |journal=ADHD Attention Deficit and Hyperactivity Disorders |language=en |volume=2 |issue=4 |pages=241–255 |doi=10.1007/s12402-010-0045-8 |pmid=21258430 |issn=1866-6116 |pmc=3000907}}</ref> and in 1994 the DSM-IV in split the diagnosis into three subtypes: ADHD inattentive type, ADHD hyperactive-impulsive type, and ADHD combined type.<ref name="Millichap_2010_chap1">{{cite book |vauthors=Millichap JG |title=Attention Deficit Hyperactivity Disorder Handbook |chapter-url=https://books.google.com/books?id=KAlq0CDcbaoC |edition=2nd |date=2010 |publisher=Springer Science |isbn=978-1-4419-1396-8 |doi=10.1007/978-1-4419-1397-5_1 |lccn=2009938108 |pages=2–3 |chapter=Definition and History of ADHD}}</ref> These terms were kept in the DSM-5 in 2013 and in the DSM-5-TR in 2022.<ref name=DSM5/><ref name=DSM5TR/> Prior to the DSM, terms included ''minimal brain damage'' in the 1930s.<ref>{{cite book |vauthors=Weiss M, Hechtman LT, Weiss G |title=ADHD in Adulthood: A Guide to Current Theory, Diagnosis, and Treatment |year=2001 |publisher=[[Taylor & Francis]] |isbn=978-0-8018-6822-1 |url=https://books.google.com/books?id=KuYvJBoB6vQC |chapter=ADHD in Adulthood: An Introduction |chapter-url=https://books.google.com/books?id=KuYvJBoB6vQC&pg=PA1 |pages=[https://books.google.com/books?id=KuYvJBoB6vQC&pg=PA34 34]}}</ref>

ADHD, its diagnosis, and its treatment have been controversial since the 1970s.<ref name="May_2008" /><ref name="Foreman_2006">{{cite journal |vauthors=Foreman DM |title=Attention deficit hyperactivity disorder: legal and ethical aspects |journal=Archives of Disease in Childhood |volume=91 |issue=2 |pages=192–194 |date=February 2006 |pmid=16428370 |pmc=2082674 |doi=10.1136/adc.2004.064576}}</ref> For example, positions differ on whether ADHD is within the normal range of behaviour,<ref name="NICE2009-part2" /><ref name="Faraone_2005">{{cite journal |vauthors=Faraone SV |title=The scientific foundation for understanding attention-deficit/hyperactivity disorder as a valid psychiatric disorder |journal=[[European Child & Adolescent Psychiatry]] |volume=14 |issue=1 |pages=1–10 |date=February 2005 |pmid=15756510 |doi=10.1007/s00787-005-0429-z |s2cid=143646869}}</ref> and to degree to which ADHD is a genetic condition.<ref>{{cite news |vauthors=Boseley S |date=30 September 2010 |title=Hyperactive children may have genetic disorder, says study |newspaper=The Guardian |url=https://www.theguardian.com/society/2010/sep/30/hyperactive-children-genetic-disorder-study |url-status=live |archive-date=8 July 2017 |archive-url=https://web.archive.org/web/20170708164457/https://www.theguardian.com/society/2010/sep/30/hyperactive-children-genetic-disorder-study}}</ref> Other areas of controversy include the use of stimulant medications in children,<ref name="May_2008" /> the method of diagnosis, and the possibility of overdiagnosis.<ref name="Cormier_2008">{{cite journal |vauthors=Cormier E |title=Attention deficit/hyperactivity disorder: a review and update |journal=Journal of Pediatric Nursing |volume=23 |issue=5 |pages=345–357 |date=October 2008 |pmid=18804015 |doi=10.1016/j.pedn.2008.01.003}}</ref> In 2009, the National Institute for Health and Care Excellence states that the current treatments and methods of diagnosis are based on the dominant view of the academic literature.<ref name="NICE2009-Diagnosis">{{cite book |title=Attention Deficit Hyperactivity Disorder: Diagnosis and Management of ADHD in Children, Young People and Adults |author=National Collaborating Centre for Mental Health |series=NICE Clinical Guidelines |volume=72 |publisher=[[British Psychological Society]] |location=Leicester |isbn=978-1-85433-471-8 |date=2009 |url=https://www.ncbi.nlm.nih.gov/books/NBK53652/ |chapter=Diagnosis |pages=[https://www.ncbi.nlm.nih.gov/books/NBK53659/#ch5.s40 116–7], [https://www.ncbi.nlm.nih.gov/books/NBK53659/#ch5.s42 119] |chapter-url=https://www.ncbi.nlm.nih.gov/books/NBK53659/ |via=NCBI Bookshelf |url-status=live |archive-url=https://web.archive.org/web/20160113133612/http://www.ncbi.nlm.nih.gov/books/NBK53652/ |archive-date=13 January 2016}}</ref>

Once neuroimaging studies were possible, studies in the 1990s provided support for the pre-existing theory that neurological differences (particularly in the [[frontal lobe]]s) were involved in ADHD. A genetic component was identified and ADHD was acknowledged to be a persistent, long-term disorder which lasted from childhood into adulthood.<ref>{{cite journal |author-link=Joseph Biederman |author-link2=Stephen Faraone |author-link5=Ming T. Tsuang |vauthors=Biederman J, Faraone SV, Keenan K, Knee D, Tsuang MT |date=July 1990 |title=Family-genetic and psychosocial risk factors in DSM-III attention deficit disorder |journal=[[Journal of the American Academy of Child and Adolescent Psychiatry]] |volume=29 |issue=4 |pages=526–533 |doi=10.1097/00004583-199007000-00004 |pmid=2387786}}</ref><ref name="Barkley_2006">{{Cite book |url=https://books.google.com/books?id=4Fvt6X3Xd-UC&pg=PT51 |title=Attention-Deficit Hyperactivity Disorder: A Handbook for Diagnosis and Treatment |vauthors=Barkley R |publisher=Guilford |year=2006 |isbn=978-1-60623-750-2 |location=New York |pages=42–5 |access-date=19 July 2022 |archive-date=2 October 2023 |archive-url=https://web.archive.org/web/20231002044633/https://books.google.com/books?id=4Fvt6X3Xd-UC&pg=PT51#v=onepage&q&f=false |url-status=live}}</ref> ADHD was split into the current three sub-types because of a field trial completed by Lahey and colleagues and published in 1994.<ref>{{cite journal |vauthors=Lahey BB, Applegate B, McBurnett K, Biederman J, Greenhill L, Hynd GW, Barkley RA, Newcorn J, Jensen P, Richters J |title=DSM-IV field trials for attention deficit hyperactivity disorder in children and adolescents |journal=[[The American Journal of Psychiatry]] |volume=151 |issue=11 |pages=1673–1685 |date=November 1994 |pmid=7943460 |doi=10.1176/ajp.151.11.1673 |lccn=22024537 |oclc=1480183 |eissn=1535-7228}}</ref> In 2021, global teams of scientists curated the International Consensus Statement compiling evidence-based findings about the disorder.<ref name="Faraone_2021" />

In 1934, Benzedrine became the first amphetamine medication approved for use in the United States.<ref name="Rasmussen_2006">{{cite journal |vauthors=Rasmussen N |title=Making the first anti-depressant: amphetamine in American medicine, 1929-1950 |journal=[[Journal of the History of Medicine and Allied Sciences]] |volume=61 |issue=3 |pages=288–323 |date=July 2006 |pmid=16492800 |doi=10.1093/jhmas/jrj039 |s2cid=24974454}}</ref> Methylphenidate was introduced in the 1950s, and [[enantiopure]] dextroamphetamine in the 1970s.<ref name="CDCTime2013" /> The use of stimulants to treat ADHD was first described in 1937.<ref>{{cite journal |vauthors=Patrick KS, Straughn AB, Perkins JS, González MA |title=Evolution of stimulants to treat ADHD: transdermal methylphenidate |journal=Human Psychopharmacology |volume=24 |issue=1 |pages=1–17 |date=January 2009 |pmid=19051222 |pmc=2629554 |doi=10.1002/hup.992}}</ref> Psychiatrist [[Charles Bradley (medical doctor)|Charles Bradley]] gave the children with behavioural disorders Benzedrine and found it improved academic performance and behaviour.<ref>{{cite journal |vauthors=Gross MD |title=Origin of stimulant use for treatment of attention deficit disorder |journal=[[American Journal of Psychiatry]] |volume=152 |issue=2 |pages=298–299 |date=February 1995 |pmid=7840374 |doi=10.1176/ajp.152.2.298b |lccn=22024537 |oclc=1480183 |eissn=1535-7228}}</ref><ref>{{Cite journal |vauthors=Brown W |date=1998 |title=Charles Bradley, M.D. |journal=[[American Journal of Psychiatry]] |issn=0002-953X |eissn=1535-7228 |lccn=22024537 |volume=155 |issue=7 |oclc=1480183 |page=968 |doi=10.1176/ajp.155.7.968}}</ref>

== Research directions ==
===Possible positive traits===
Possible positive traits of ADHD are a new avenue of research, and therefore limited.

A 2020 review found that creativity [[Creativity and mental health|may be associated]] with ADHD symptoms, particularly [[divergent thinking]] and quantity of creative achievements, but not with the disorder of ADHD itself&nbsp;– i.e. it has not been found to be increased in people diagnosed with the disorder, only in people with subclinical symptoms or those that possess traits associated with the disorder. Divergent thinking is the ability to produce creative solutions which differ significantly from each other and consider the issue from multiple perspectives. Those with ADHD symptoms could be advantaged in this form of creativity as they tend to have diffuse attention, allowing rapid switching between aspects of the task under consideration; flexible [[Associative memory (psychology)|associative memory]], allowing them to remember and use more distantly related ideas which is associated with creativity; and impulsivity, allowing them to consider ideas which others may not have.<ref name="Hoogman_2020">{{cite journal |vauthors=Hoogman M, Stolte M, Baas M, Kroesbergen E |title=Creativity and ADHD: A review of behavioral studies, the effect of psychostimulants and neural underpinnings |journal=[[Neuroscience & Biobehavioral Reviews]] |volume=119 |pages=66–85 |date=December 2020 |pmid=33035524 |doi=10.1016/j.neubiorev.2020.09.029 |hdl=1874/409179 |url=https://repository.ubn.ru.nl//bitstream/handle/2066/227072/227072.pdf |access-date=28 August 2023 |url-status=live |s2cid=222142805 |archive-url=https://web.archive.org/web/20230906213830/https://repository.ubn.ru.nl//bitstream/handle/2066/227072/227072.pdf |archive-date=6 September 2023}}</ref>

===Possible biomarkers for diagnosis===
Reviews of ADHD [[Biomarker (medicine)|biomarker]]s have noted that platelet [[monoamine oxidase]] expression, urinary [[norepinephrine]], urinary [[3-Methoxy-4-hydroxyphenylglycol|MHPG]], and urinary [[phenethylamine]] levels consistently differ between ADHD individuals and non-ADHD controls. These parameters could serve as prognostic biomarkers for ADHD, but more research is needed to establish their prognostic utility. Urinary and [[blood plasma]] phenethylamine concentrations are lower in ADHD individuals relative to controls.<ref>{{Cite journal |last1=Kusaga |first1=Akira |last2=Yamashita |first2=Yushiro |last3=Koeda |first3=Tastuya |last4=Hiratani |first4=Michio |last5=Kaneko |first5=Mika |last6=Yamada |first6=Shigeto |last7=Matsuishi |first7=Toyojiro |date=2002 |title=Increased urine phenylethylamine after methylphenidate treatment in children with ADHD |url=https://onlinelibrary.wiley.com/doi/10.1002/ana.10302 |journal=Annals of Neurology |language=en |volume=52 |issue=3 |pages=372–374 |doi=10.1002/ana.10302 |pmid=12205654 |issn=1531-8249 |url-access=subscription}}</ref><ref>{{Cite journal |last1=Baker |first1=G. B. |last2=Bornstein |first2=R. A. |last3=Rouget |first3=A. C. |last4=Ashton |first4=S. E. |last5=van Muyden |first5=J. C. |last6=Coutts |first6=R. T. |date=1 January 1991 |title=Phenylethylaminergic mechanisms in attention-deficit disorder |url=https://www.sciencedirect.com/science/article/abs/pii/0006322391902073 |journal=[[Biological Psychiatry (journal)|Biological Psychiatry]] |volume=29 |issue=1 |pages=15–22 |doi=10.1016/0006-3223(91)90207-3 |pmid=2001444 |issn=0006-3223 |url-access=subscription}}</ref> The two most commonly prescribed drugs for ADHD, [[amphetamine]] and [[methylphenidate]], increase phenethylamine [[biosynthesis]] in treatment-responsive individuals with ADHD.<ref name="Berry_2007">{{cite journal |vauthors=Berry MD |title=The potential of trace amines and their receptors for treating neurological and psychiatric diseases |journal=Reviews on Recent Clinical Trials |volume=2 |issue=1 |pages=3–19 |date=January 2007 |pmid=18473983 |doi=10.2174/157488707779318107 |quote=Although there is little direct evidence, changes in trace amines, in particular PE, have been identified as a possible factor for the onset of attention deficit/hyperactivity disorder (ADHD). ... Further, amphetamines, which have clinical utility in ADHD, are good ligands at trace amine receptors. Of possible relevance in this aspect is modafanil, which has shown beneficial effects in ADHD patients and has been reported to enhance the activity of PE at TAAR1. Conversely, methylphenidate, ...showed poor efficacy at the TAAR1 receptor. In this respect it is worth noting that the enhancement of functioning at TAAR1 seen with modafanil was not a result of a direct interaction with TAAR1. |citeseerx=10.1.1.329.563}}</ref> Lower urinary phenethylamine concentrations are associated with symptoms of inattentiveness in ADHD individuals.<ref name="Scassellati_2012">{{cite journal |vauthors=Scassellati C, Bonvicini C, Faraone SV, Gennarelli M |title=Biomarkers and attention-deficit/hyperactivity disorder: a systematic review and meta-analyses |journal=[[Journal of the American Academy of Child and Adolescent Psychiatry]] |volume=51 |issue=10 |pages=1003–1019.e20 |date=October 2012 |pmid=23021477 |doi=10.1016/j.jaac.2012.08.015}}</ref>

== See also ==
{{Portal|Medicine}}
* {{anl|Attention deficit hyperactivity disorder controversies}}
* [[Directed attention fatigue]] – A temporary state sharing many of the symptoms of ADHD
* {{anl|Self-medication}}

== References ==
{{reflist}}

== Further reading ==
{{refbegin|30em}}
* {{cite book |last1=Barkley|first1= Russell A |author-link1=Russell Barkley|last2=Benton|first2= CM |title=Taking charge of adult ADHD: proven strategies to succeed at work, at home, and in relationships |publisher=[[Guilford Press]] |year=2022 |edition=2nd |isbn=978-1-4625-4752-4 |oclc=1251741330}}
* {{cite book |last1=Hallowell |first1=EM|author-link=Edward Hallowell (psychiatrist)|last2=Ratey|first2= John J. |author-link2=John Ratey|title=Driven to distraction: recognizing and coping with attention deficit disorder from childhood through adulthood |publisher=Anchor Books |year=2011 |edition=1 |isbn=978-0-307-74315-2 |oclc=1200786886}}
* {{cite book |vauthors=Hinshaw SP, Scheffler RM |title=The ADHD Explosion: Myths, Medication, Money, and Today's Push for Performance |isbn=978-0-19-979055-5 |year=2014 |publisher=[[Oxford University Press]]}}
* {{cite book |vauthors=Mate G |title=Scattered minds: a new look at the origins and healing of attention deficit disorder |publisher=[[Vintage Books]] |year=1999 |isbn=978-0-676-97259-7 |location=Canada |oclc=48795973}}
* {{cite book |vauthors=Schwarz A |title=ADHD Nation: Children, Doctors, Big Pharma, and the Making of an American Epidemic |year=2016 |url=https://archive.org/details/adhdnationchildr0000schw_d3y4 |publisher=Scribner |oclc=951612166 |isbn=978-1-5011-0591-3}}
* {{cite book |vauthors=Young JL |title=[[ADHD Grown Up: A Guide to Adolescent and Adult ADHD]] |date=9 January 2007 |publisher=[[W. W. Norton & Company]]}}
* {{cite journal |vauthors=Pliszka S |title=Practice parameter for the assessment and treatment of children and adolescents with attention-deficit/hyperactivity disorder |journal=[[Journal of the American Academy of Child and Adolescent Psychiatry]] |volume=46 |issue=7 |pages=894–921 |date=July 2007 |pmid=17581453 |doi=10.1097/chi.0b013e318054e724 |s2cid=602465 |doi-access=free}}
* {{cite journal |vauthors=Reaser A, Prevatt F, Petscher Y, Proctor B |year=2007 |title=The learning and study strategies of college students with ADHD |journal=Psychology in the Schools |volume=44 |issue=6 |pages=627–638 |issn=0033-3085 |eissn=1520-6807 |lccn=64009353 |oclc=1763062 |publisher=[[Wiley-Blackwell]] |doi=10.1002/pits.20252}}
{{refend}}

== External links ==
* National Institute of Mental Health. [https://web.archive.org/web/20210508154716/https://www.nimh.nih.gov/topics/topic-page-adhd NIMH Pages About Attention-Deficit/Hyperactivity Disorder (ADHD).] National Institutes of Health (NIH), U.S. Department of Health and Human Services.

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| OMIM = 143465
| DiseasesDB = 6158
| Curlie =https://dmoz-odp.org/Health/Mental_Health/Disorders/Neurodevelopmental/ADD_and_ADHD/
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{{ADHD|state=uncollapsed}}
{{ADHD pharmacotherapies}}
{{Amphetamine}}
{{Emotional and behavioral disorders}}
{{Mental and behavioral disorders|selected=childhood}}
{{Digital media use and mental health}}
{{Authority control}}

[[Category:Attention deficit hyperactivity disorder| ]]
[[Category:1987 neologisms]]
[[Category:Ailments of unknown cause]]
[[Category:Amphetamine]]
[[Category:Attention disorders]]
[[Category:Learning disabilities]]
[[Category:Methylphenidate]]
[[Category:Wikipedia medicine articles ready to translate (full)]]
[[Category:Wikipedia neurology articles ready to translate]]