View source for Conversion disorder

{{short description|Former psychiatric diagnosis}}
{{use mdy dates|date=December 2023}}
{{Infobox medical condition
| name = Conversion disorder
| field = [[Psychiatry]], [[Neurology]]
| symptoms = [[Numbness]], [[weakness]], [[movement disorder|movement problems]], [[psychogenic non-epileptic seizure|non-epileptic seizures]], [[tremor]], [[fainting]], [[speech disorder|trouble speaking]], [[deafness|impaired hearing]] and [[blindness|vision]], [[Dysphagia|trouble swallowing]]
| complications = 
| onset = 
| duration = 
| types = 
| risks = Long term [[Psychological stress|stress]]
| diagnosis = 
| differential = 
| prevention = 
| treatment = [[Cognitive behavioral therapy]], [[medication]], [[physical therapy|physical]]/[[occupational therapy]]
| medication = 
| prognosis = 
| frequency = 
| deaths = 
}}
'''Conversion disorder''' ('''CD''') was a formerly diagnosed [[psychiatric disorder]] characterized by abnormal sensory experiences and movement problems during periods of high [[psychological stress]]. Individuals diagnosed with CD presented with highly distressing [[neurological]] symptoms such as [[numbness]], [[blindness]], [[paralysis]], or [[Convulsion|convulsions]], none of which were consistent with a well-established [[Disease|organic cause]] and could be traced back to a [[Trauma trigger|psychological trigger]].<ref>{{Citation |last1=Peeling |first1=Jessica L. |title=Functional Neurologic Disorder |date=2024 |work=StatPearls |url=https://www.ncbi.nlm.nih.gov/books/NBK551567/ |access-date=2024-06-30 |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=31855394 |last2=Muzio |first2=Maria Rosaria}}</ref> CD is no longer a diagnosis in the [[World Health Organization|WHO]]'s [[ICD-11]] or [[American Psychiatric Association|APA]]'s [[DSM-5]] and was superseded by [[functional neurologic disorder]] (FND), a similar diagnosis that notably removed the requirement for a psychological stressor to be present. 

It was thought that these symptoms arise in response to stressful situations affecting a patient's mental health. Individuals diagnosed with conversion disorder have a greater chance of experiencing certain psychiatric disorders including [[Anxiety disorder|anxiety disorders]], [[Mood disorder|mood disorders]], and [[Personality disorder|personality disorders]] compared to those diagnosed with [[Neurological disorder|neurological disorders]].<ref>{{Citation |last1=Peeling |first1=Jessica L. |title=Functional Neurologic Disorder |date=2024 |work=StatPearls |url=https://www.ncbi.nlm.nih.gov/books/NBK551567/ |access-date=2024-06-30 |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=31855394 |last2=Muzio |first2=Maria Rosaria}}</ref> 

Conversion disorder was partly retained in the [[DSM-5-TR]] and ICD-11, but was renamed to [[functional neurological symptom disorder]] (FNSD) and dissociative neurological symptom disorder (DNSD), respectively. FNSD covers a similar range of symptoms found in conversion disorder, but does not include the requirements for a psychological [[stressor]] to be present. The new criteria no longer require feigning to be disproven before diagnosing FNSD. A fifth criterion describing a limitation in sexual functioning that was included in the [[DSM-IV]] was removed in the DSM-5 as well.<ref>Kanaan, R.A.A. (2022).</ref> The ICD-11 classifies DNSD as a [[Dissociative disorders|dissociative disorder]] with unspecified neurological symptoms<!-- there are two references because CD is a synonym of 6B60.Z but the ICD-11's informative content is in 6B60 -->.<ref name="ICD-11 (dissociative neurological symptoms)">[[World Health Organization]] (2023). "{{ICD11|6B60|1069443471}} Dissociative neurological with unspecified symptoms ". ''[[International Classification of Diseases]], eleventh  revision – ICD-11''. Genova – [https://icd.who.int icd.who.int].</ref><ref name="ICD-11 (dissociative neurological symptom disorder with unspecified symptoms)">[[World Health Organization]] (2023). "{{ICD11|6B60.Z}} Dissociative neurological symptom disorder, with unspecified symptoms ". ''[[International Classification of Diseases]], eleventh  revision – ICD-11''. Genova – [https://icd.who.int icd.who.int].</ref>

==Signs and symptoms==
Conversion disorder presented with symptoms following exposure to a certain stressor, typically associated with [[Psychological trauma|trauma]] or [[psychological distress]]. Usually, the physical symptoms of the disorder affect the senses or movement. Common symptoms included [[blindness]], partial or total [[paralysis]], [[Muteness|inability to speak]], [[deafness]], [[Hypoesthesia|numbness]], [[Dysphagia|difficulty swallowing]], [[Fecal incontinence|incontinence]], [[Balance disorder|balance problems]], [[Psychogenic non-epileptic seizure|non-epileptic seizures]], [[tremor]]s, and difficulty walking. Feelings of breathlessness were said to have possibly indicated conversion disorder or [[sleep paralysis]].<ref name="National Institute of Health, 2012"/>

Sleep paralysis and [[narcolepsy]] can be ruled out with [[Sleep study|sleep tests]]. These symptoms were attributed to conversion disorder when a medical explanation for the conditions cannot be found.<ref name="National Institute of Health, 2012">{{cite web | url=https://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001950/ | archive-url=https://web.archive.org/web/20110214044208/http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001950 | archive-date=February 14, 2011 | title=Conversion disorder | publisher=National Center for Biotechnology Information, U.S. National Library of Medicine | date=2012-11-17 | access-date=25 October 2013}}</ref> Symptoms of conversion disorder usually occur suddenly. Conversion disorder was typically observed in people ages 10 to 35,<ref name = dsm>Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, American Psychiatric Association</ref> affecting between 0.011% and 0.5% of the general population.<ref name="Tollison">{{Cite book| url = https://books.google.com/books?id=BbmI8FCssdEC| title = Practical Pain Management| last1 = Tollison| first1 = C. David| last2 = Satterthwaite| first2 = John R.| last3 = Tollison| first3 = Joseph W.| date = 2002-01-01| publisher = Lippincott Williams & Wilkins| isbn = 978-0-7817-3160-7| language = en}}</ref>

Conversion disorder presented motor or sensory symptoms including:

Motor symptoms or deficits:
* Impaired coordination or balance
* Weakness/paralysis of a limb or the entire body (hysterical paralysis or motor conversion disorders)
* Impairment or loss of speech (hysterical [[aphonia]])
* Difficulty swallowing ([[dysphagia]]) or a sensation of a lump in the throat
* Urinary retention
* [[Psychogenic non-epileptic seizures]] or convulsions
* Persistent [[dystonia]] 
* Tremor, [[myoclonus]] or other movement disorders
* Gait problems ([[astasia-abasia]])
* Loss of consciousness (fainting)

Sensory symptoms or deficits:
* Impaired vision, double vision
* Impaired hearing
* Loss or disturbance of touch or pain sensation

Conversion symptoms typically do not conform to known anatomical pathways and physiological mechanisms. It has sometimes been stated that the presenting symptoms tend to reflect the patient's own understanding of anatomy and that the less medical knowledge a person has, the more implausible are the presenting symptoms.<ref name = dsm/> However, no systematic studies have yet been performed to substantiate this statement.<ref>{{Citation |last1=Peeling |first1=Jessica L. |title=Conversion Disorder |date=2023 |url=https://www.ncbi.nlm.nih.gov/books/NBK551567/ |work=StatPearls |access-date=2023-05-05 |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=31855394 |last2=Muzio |first2=Maria Rosaria}}</ref>

[[Sexual dysfunction]] and [[pain]] were also considered symptoms of conversion disorder, but if a patient only has these symptoms, they should be diagnosed with [[Sexual dysfunction#Sexual pain disorders|sexual pain disorder]] or [[pain disorder]].<ref>{{Cite book |last1=Stern |first1=Theodore A. |title=Massachusetts General Hospital Handbook of General Hospital Psychiatry |last2=Fricchione |first2=Gregory L. |last3=Rosenbaum |first3=Jerrold F. |date=2010 |publisher=Elsevier |isbn=978-1-4377-1927-7 |edition=6th |pages=211–236}}</ref>

==Diagnosis==
===Definition===
Conversion disorder is now partly contained under [[Functional neurologic disorder|functional neurological symptom disorder]] (FNSD). In cases of conversion disorder, there is a psychological stressor.

The diagnostic criteria for functional neurologic symptom disorder, as set out in DSM-5, are:

{{ordered list|list_style_type=lower-alpha
| The patient has at least one symptom of altered voluntary motor or sensory function.
| Clinical findings provide evidence of incompatibility between the symptom and recognised neurological or medical conditions.
| The symptom or deficit is not better explained by another medical or mental disorder.
| The symptom or deficit causes clinically significant distress or impairment in social, occupational, or other important areas of functioning or warrants medical evaluation.
}}
'''Specify type of symptom or deficit as:'''
* With weakness or paralysis
* With abnormal movement (e.g. tremor, [[dystonic]] movement, [[myoclonus]], gait disorder)
* With swallowing symptoms
* With speech symptoms (e.g. [[dysphonia]], slurred speech)
* With attacks or seizures
* With amnesia or memory loss
* With special sensory loss symptoms (e.g. visual blindness, olfactory loss, or hearing disturbance)
* With mixed symptoms.
'''Specify if:'''
* Acute episode: symptoms present for less than six months
* Persistent: symptoms present for six months or more.<ref>{{Cite web|url = http://bestpractice.bmj.com/best-practice/monograph/989/diagnosis/criteria.html|title = Conversion and somatic symptom disorders|access-date = 25 November 2015}}</ref>
'''Specify if:'''
* Psychological stressor (conversion disorder)
* No psychological stressor ([[functional neurological symptom disorder|functional neurologic symptom disorder]])

===Exclusion of neurological disease===

Conversion disorder presents with symptoms that typically resemble a [[neurological disorder]] such as [[stroke]], [[multiple sclerosis]], [[epilepsy]], [[hypokalemic periodic paralysis]], or [[narcolepsy]]. The neurologist must carefully exclude neurological disease, through examination and appropriate investigations.<ref name="Stone_2005">{{cite journal |vauthors=Stone J, Carson A, Sharpe M | title = Functional symptoms and signs in neurology: assessment and diagnosis | journal = J. Neurol. Neurosurg. Psychiatry | volume = 76 | pages = i2–12 | year = 2005 | issue = Suppl 1 | pmid = 15718217 | pmc = 1765681 | doi = 10.1136/jnnp.2004.061655 }}</ref> However, it is not uncommon for patients with neurological disease to also have conversion disorder.<ref name="pmid1469401">{{cite journal | author = Eames P | title = Hysteria following brain injury | journal = J. Neurol. Neurosurg. Psychiatry | volume = 55 | issue = 11 | pages = 1046–53 | year = 1992 | pmid = 1469401 | pmc = 1015291 | doi = 10.1136/jnnp.55.11.1046}}</ref>

In excluding neurological disease, the neurologist has traditionally relied partly on the presence of positive signs of conversion disorder (i.e., certain aspects of the presentation that were thought to be rare in neurological disease but common in conversion disorder). The validity of many of these signs has been questioned by a study showing that they also occur in neurological disease.<ref name="pmid3760849">{{cite journal |vauthors=Gould R, Miller BL, Goldberg MA, Benson DF | title = The validity of hysterical signs and symptoms | journal = J. Nerv. Ment. Dis. | volume = 174 | issue = 10 | pages = 593–7 | year = 1986 | pmid = 3760849 | doi = 10.1097/00005053-198610000-00003| s2cid = 38888726 }}</ref> One such symptom, for example, is ''la belle indifférence'', described in DSM-IV as "a relative lack of concern about the nature or implications of the symptoms". In a 2006 study, no evidence was found that patients with [[functional symptom]]s are any more likely to exhibit this than patients with a confirmed organic disease.<ref name="pmid16507959">{{cite journal |vauthors=Stone J, Smyth R, Carson A, Warlow C, Sharpe M | title = La belle indifférence in conversion symptoms and hysteria: systematic review | journal = Br J Psychiatry | volume = 188 | pages = 204–9 | year = 2006 | pmid = 16507959 | doi = 10.1192/bjp.188.3.204 | doi-access = free }}</ref> In the DSM-5, ''la belle indifférence'' was removed as a diagnostic criterion.

Another feature thought to be important was that symptoms tended to be more severe on the non-dominant, usually left side of the body. There have been a number of theories about this, such as the relative involvement of cerebral hemispheres in emotional processing, or more simply, that it was "easier" to live with a functional deficit on the non-dominant side. However, a literature review of 121 studies established that this was not true, with [[publication bias]] the most likely explanation for this commonly held view.<ref name="pmid12397155">{{cite journal |vauthors=Stone J, Sharpe M, Carson A, Lewis SC, Thomas B, Goldbeck R, Warlow CP | title = Are functional motor and sensory symptoms really more frequent on the left? A systematic review | journal = J. Neurol. Neurosurg. Psychiatry | volume = 73 | issue = 5 | pages = 578–81 | year = 2002 | pmid = 12397155 | pmc = 1738113 | doi = 10.1136/jnnp.73.5.578}}</ref> Although agitation is often assumed to be a positive sign of conversion disorder, release of [[epinephrine]] is a well-demonstrated cause of paralysis from [[hypokalemic periodic paralysis]].<ref>{{cite web|url=https://www.uni-ulm.de/fileadmin/website_uni_ulm/med.inst.040/Dokumente/owner.html |title=Segal MM, Jurkat-Rott K, Levitt J, Lehmann-Horn F, Hypokalemic periodic paralysis—an owner's manual |publisher=Uni-ulm.de |date=2009-06-05 |access-date=2013-11-30}}</ref>

Misdiagnosis does sometimes occur. In a highly influential<ref name="pmid14286998">{{cite journal | author = Slater E | title = Diagnosis of Hysteria | journal = Br Med J | volume = 1 | issue = 5447 | pages = 1395–9 | year = 1965 | pmid = 14286998 | pmc = 2166300 | doi = 10.1136/bmj.1.5447.1395}}</ref> study from the 1960s, [[Eliot Slater]] demonstrated that misdiagnoses had occurred in one third of his 112 patients with conversion disorder.<ref name="pmid5857619">{{cite journal |vauthors=Slater ET, Glithero E | title = A follow-up of patients diagnosed as suffering from "hysteria" | journal = J Psychosom Res | volume = 9 | issue = 1 | pages = 9–13 | year = 1965 | pmid = 5857619 | doi = 10.1016/0022-3999(65)90004-8}}</ref> Later authors have argued that the paper was flawed.<ref name="ReferenceB">{{cite journal|year=2005|title=Eliot Slater's myth of the non-existence of hysteria|journal=J R Soc Med|volume=98|issue=12|pages=547–8|doi=10.1177/014107680509801214|pmc=1299341|pmid=16319432|vauthors=Stone J, Warlow C, Carson A, Sharpe M}}</ref><ref>Ron M, "The Prognosis of Hysteria" In P. Halligan, C. Bass, J. Marshall (Eds.) Hysterical Conversion: clinical and theoretical perspectives (pp. 73–87). Oxford: Oxford University Press.</ref> A 2005 meta-analysis has shown that misdiagnosis rates since that paper was published are around four percent, the same as for other neurological diseases.<ref name="Stone_2005"/>

===Psychological mechanism===

The psychological mechanism of conversion can be the most difficult aspect of a conversion disorder diagnosis. Even if there is a clear antecedent trauma or other possible psychological trigger, it is still not clear exactly how this gives rise to the symptoms observed. Patients with medically unexplained neurological symptoms may not have any psychological stressor, hence the use of the term "functional neurological symptom disorder" in the DSM-5, as opposed to "conversion disorder", and the DSM-5's removal of the need for a psychological trigger. The change of name in the DSM-5 also came with a change of criteria. There was a removal of connection to sexual functioning as well as relation to any other medical condition. There was also an added connection to social and occupational functioning.<ref>Kanaan, R.A.A. (2022).</ref>

==Treatment==

Treatments for conversion disorder included hypnosis, psychotherapy, physical therapy, and stress management. Treatment plans will consider duration and presentation of symptoms and may include one or multiple of the above treatments.<ref name = Mayo>{{cite web | url=http://www.mayoclinic.com/health/conversion-distorder/DS00877 | title=Conversion disorder | publisher=Mayo Foundation for Medical Education and Research | access-date=25 October 2013}}</ref> This may include the following:<ref name="pmid15718216">{{cite journal |vauthors=Stone J, Carson A, Sharpe M | title = Functional symptoms in neurology: management | journal = J. Neurol. Neurosurg. Psychiatry | volume = 76 | pages = i13–21 | year = 2005 | issue = Suppl 1 | pmid = 15718216 | pmc = 1765682 | doi = 10.1136/jnnp.2004.061663 }}</ref>
#[[Occupational therapy]] to maintain autonomy in activities of daily living.<ref>{{cite web |url=http://www.doctorsofusc.com/condition/document/96743 |title=Conversion Disorder &#124; Doctors of USC |website=www.doctorsofusc.com |access-date=13 January 2022 |archive-url=https://web.archive.org/web/20080822013004/http://www.doctorsofusc.com/condition/document/96743 |archive-date=22 August 2008 }}</ref>
#Treatment of comorbid [[clinical depression|depression]] or [[Anxiety disorder|anxiety]] if present.{{citation needed|date=January 2022}}.
#Educating patients on the causes of their symptoms might help them learn to manage both the psychiatric and physical aspects of their condition. Psychological counseling is often warranted given the known relationship between conversion disorder and emotional trauma. This approach ideally takes place alongside other types of treatment.{{citation needed|date=January 2022}}
#Medications such as [[Serotonin–norepinephrine reuptake inhibitor|serotonin–norepinephrine reuptake inhibitors]] (SNRIs), a class of antidepressants, and [[Sedative|sedatives]] such as [[Benzodiazepine|benzodiazepines]] may help reduce stress and also relieve or prevent symptoms from occurring.{{citation needed|date=January 2022}}

There is little evidence-based treatment of conversion disorder.<ref>{{Cite journal|last1=Ganslev|first1=Christina A.|last2=Storebø|first2=Ole Jakob|last3=Callesen|first3=Henriette E.|last4=Ruddy|first4=Rachel|last5=Søgaard|first5=Ulf|date=17 July 2020|title=Psychosocial interventions for conversion and dissociative disorders in adults|journal=The Cochrane Database of Systematic Reviews|volume=2020|issue=7|article-number=CD005331|doi=10.1002/14651858.CD005331.pub3|issn=1469-493X|pmc=7388313|pmid=32681745}}</ref> Other treatments such as [[cognitive behavioral therapy]] (CBT), [[hypnosis]], [[EMDR]], [[psychodynamic psychotherapy]], [[transcranial magnetic stimulation]] (TMS), [[virtual reality therapy]], and [[EEG]] brain [[biofeedback]] need further trials. [[Psychoanalytic]] treatment may possibly be helpful.<ref>{{cite journal | pmc = 3091899 | pmid=21502352 | doi=10.1503/cmaj.110490 | volume=183 | issue=8 | title=Conversion disorder: advances in our understanding | year=2011 | journal=CMAJ | pages=915–20 | author=Feinstein A}}</ref> Most studies assessing the efficacy of these treatments are of poor quality and larger, better controlled studies are urgently needed. CBT is the most common treatment, with a 13% improvement rate.

==Prognosis==

[[Empirical studies]] have found that the [[prognosis]] for conversion disorder varies widely, with some cases resolving in weeks, and others enduring for years or decades.<ref>{{cite journal|last1=Mace|first1=CJ|last2=Trimble|first2=MR|title=Ten-year prognosis of conversion disorder.|journal=The British Journal of Psychiatry|date=September 1996|volume=169|issue=3|pages=282–8|pmid=8879713|doi=10.1192/bjp.169.3.282|s2cid=7549659 }}</ref><ref>{{cite journal|last1=Couprie|first1=W|last2=Wijdicks|first2=EF|last3=Rooijmans|first3=HG|last4=van Gijn|first4=J|title=Outcome in conversion disorder: a follow up study.|journal=Journal of Neurology, Neurosurgery, and Psychiatry|date=June 1995|volume=58|issue=6|pages=750–2|pmid=7608683|doi=10.1136/jnnp.58.6.750|pmc=1073562}}</ref> Although patients may go into remission, they can relapse at any point.

==Epidemiology==
===Frequency===

Information on the frequency of conversion disorder is limited, in part due to the complexities of the diagnostic process. In neurology clinics, the reported [[prevalence]] of unexplained symptoms among new patients is very high, between 30 and 60%.<ref name="Carson_2000">{{cite journal |vauthors=Carson AJ, Ringbauer B, Stone J, McKenzie L, Warlow C, Sharpe M | title = Do medically unexplained symptoms matter? A prospective cohort study of 300 new referrals to neurology outpatient clinics | journal = J. Neurol. Neurosurg. Psychiatry | volume = 68 | issue = 2 | pages = 207–10 | year = 2000 | pmid = 10644789 | pmc = 1736779 | doi = 10.1136/jnnp.68.2.207}}</ref><ref name="pmid11448704">{{cite journal |vauthors=Nimnuan C, Hotopf M, Wessely S | title = Medically unexplained symptoms: an epidemiological study in seven specialities | journal = J Psychosom Res | volume = 51 | issue = 1 | pages = 361–7 | year = 2001 | pmid = 11448704 | doi = 10.1016/s0022-3999(01)00223-9}}</ref><ref name="pmid14999491">{{cite journal |vauthors=Snijders TJ, de Leeuw FE, Klumpers UM, Kappelle LJ, van Gijn J | title = Prevalence and predictors of unexplained neurological symptoms in an academic neurology outpatient clinic—an observational study | journal = J. Neurol. | volume = 251 | issue = 1 | pages = 66–71 | year = 2004 | pmid = 14999491 | doi = 10.1007/s00415-004-0273-y | s2cid = 8191138 }}</ref> However, diagnosis of conversion disorder typically required an additional psychiatric evaluation, and since few patients will see a psychiatrist,<ref name="pmid11110993">{{cite journal |vauthors=Crimlisk HL, Bhatia KP, Cope H, David AS, Marsden D, Ron MA | title = Patterns of referral in patients with medically unexplained motor symptoms | journal = J Psychosom Res | volume = 49 | issue = 3 | pages = 217–9 | year = 2000 | pmid = 11110993 | doi = 10.1016/s0022-3999(00)00167-7}}</ref> it is unclear what proportion of the unexplained symptoms are actually due to the disorder. In 1976, large scale psychiatric registers in the U.S. and Iceland found [[Incidence (epidemiology)|incidence rate]]s of 22 and 11 newly diagnosed cases per 100,000 person-years, respectively.<ref name="Stefansson">{{cite journal |vauthors=Stefánsson JG, Messina JA, Meyerowitz S | title = Hysterical neurosis, conversion type: clinical and epidemiological considerations | journal = [[Acta Psychiatr Scand]] | volume = 53 | issue = 2 | pages = 119–38 | year = 1976 | pmid = 1251758 | doi = 10.1111/j.1600-0447.1976.tb00066.x| s2cid = 39279206 }}</ref> In 2002, some estimates claim that in the general population, between 0.011% and 0.5% of the population have conversion disorder.<ref name="Tollison"/>

===Culture===

Although it is often thought that the frequency of conversion may be higher outside of the West, perhaps in relation to cultural and medical attitudes, evidence of this is limited.<ref name="Akagi, H. 2001, pp. 73">Akagi, H. & House, A.O., 2001, "The epidemiology of hysterical conversion". In P. Halligan, C. Bass, J. Marshall (Eds.) ''Hysterical Conversion: clinical and theoretical perspectives'' (pp. 73–87). Oxford: Oxford University Press.</ref> A 2007 community survey of urban Turkey found a prevalence of 5.6%.<ref name="Deveci">{{cite journal |vauthors=Deveci A, Taskin O, Dinc G, Yilmaz H, Demet MM, Erbay-Dundar P, Kaya E, Ozmen E | title = Prevalence of pseudoneurologic conversion disorder in an urban community in Manisa, Turkey | journal = Soc Psychiatry Psychiatr Epidemiol | volume = 42 | issue = 11 | pages = 857–64 | year = 2007 | pmid = 17639308 | doi = 10.1007/s00127-007-0233-9 | s2cid = 35026784 }}</ref> Many authors have found occurrence of conversion to be more frequent in rural, lower socio-economic groups, where technological investigation of patients is limited and people may know less about medical and psychological concepts.<ref name="Stefansson" /><ref name="pmid1950631">{{cite journal |vauthors=Tomasson K, Kent D, Coryell W | title = Somatization and conversion disorders: comorbidity and demographics at presentation | journal = Acta Psychiatr Scand | volume = 84 | issue = 3 | pages = 288–93 | year = 1991 | pmid = 1950631 | doi = 10.1111/j.1600-0447.1991.tb03146.x| s2cid = 7567719 }}</ref><ref name="pmid12563551">{{cite journal |vauthors=Kuloglu M, Atmaca M, Tezcan E, Gecici O, Bulut S | title = Sociodemographic and clinical characteristics of patients with conversion disorder in Eastern Turkey | journal = Soc Psychiatry Psychiatr Epidemiol | volume = 38 | issue = 2 | pages = 88–93 | year = 2003 | pmid = 12563551 | doi = 10.1007/s00127-003-0608-5 | s2cid = 21829547 }}</ref>

===Gender===

In recent surveys of conversion disorder, females predominate, with between two and six female patients for every male. Some research suggests however that this gender disparity may be confounded by higher rates of violence against women.<ref>{{cite journal
| last1      = Kletenik
| first1     = I
| last2      = Sillau
| first2     = SH
| last3      = Attaripour Isfahani
| first3     = S
| last4      = LaFaver
| first4     = K
| last5      = Hallett
| first5     = M
| last6      = Berman
| first6     = BD
|date=2019-11-29
| title      = Gender as a Risk Factor for Functional Movement Disorders: The Role of Sexual Abuse
| journal    = Movement Disorders Clinical Practice
| volume     = 7
| issue      = 2
| pages      = 177–181
| doi        = 10.1002/mdc3.12863
| pmid       = 32071936
| pmc = 7011626
| doi-access= free
}}</ref>
<ref>{{Cite journal | vauthors = Kletenik I, Holden SK, Sillau SH, O'Connell N, MacGillivray L, Mack J, Haddock B, Ashworth Dirac M, David AS, Nicholson TR, Attaripour Isfahani SN, Maurer CW, Lidstone SC, Hallett M, LaFaver K, Berman BD, Stone J | date=Jan 2022 | title=Gender disparity and abuse in functional movement disorders: a multi-center case-control study | journal=J Neurol | volume=269 | issue=6 | pages=3258–3263 | language=en | doi=10.1007/s00415-021-10943-6| pmid=35098346| pmc=10202134 | s2cid=246413303 }}</ref>

===Age===

Conversion disorder may present at any age, but is rare in children younger than ten or in the elderly. Studies suggest a peak onset in the mid-to-late 30s.<ref name="Carson_2000"/><ref name="Stefansson" /><ref name="Deveci" />

==History==

The first evidence of hysteria dates back to 1900 B.C., when the symptoms were blamed on the uterus moving within the female body. The treatment varied "depending on the position of the uterus, which must be forced to return to its natural position. If the uterus had moved upwards, this could be done by placing malodorous and acrid substances near the woman's mouth and nostrils, while scented ones were placed near her vagina; on the contrary, if the uterus had lowered, the document recommends placing the acrid substances near her vagina and the perfumed ones near her mouth and nostrils."<ref name="Tasca 110–119">{{Cite journal| last1 = Tasca| first1 = Cecilia| last2 = Rapetti| first2 = Mariangela| last3 = Carta| first3 = Mauro Giovanni| last4 = Fadda| first4 = Bianca| date = 2012-10-19| title = Women And Hysteria In The History Of Mental Health| journal = Clinical Practice and Epidemiology in Mental Health| volume = 8| pages = 110–119| doi = 10.2174/1745017901208010110| issn = 1745-0179| pmc = 3480686| pmid = 23115576}}</ref>

In Greek mythology, [[hysteria]], a similarly described condition, was thought to be caused by a lack of orgasms, uterine melancholy, and not procreating. [[Plato]], [[Aristotle]], and [[Hippocrates]] believed that a lack of sex causes complications in the uterus. Many Greeks believed it could be prevented and cured with [[wine]] and [[Orgy|orgies]]. Hippocrates argued that a lack of regular [[sexual intercourse]] led to the uterus producing toxic fumes, causing it to move in the body. Therefore, he argued, all women should be married and enjoy a satisfactory sexual life.<ref name="Tasca 110–119"/>

Donald Capps argues that the diseases [[Miracles of Jesus|Jesus allegedly healed]], such as paralysis and blindness, were actually forms of conversion disorder. He describes Jesus as a "village psychiatrist", who believed that his words had power.<ref>{{Cite journal |last=Capps |first=Donald |date=2010 |title=Jesus the village psychiatrist: a summary |url=http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S0259-94222010000100028 |journal=HTS Theological Studies |volume=66 |issue=1 |via=Scielo}}</ref>

From the 13th century, women with hysteria were exorcised, as it was believed that they were possessed by the devil. It was believed that if doctors could not find the cause of a disease or illness, it must be caused by the devil.<ref name="Tasca 110–119"/>

At the beginning of the 16th century, women were sexually stimulated by midwives in order to relieve their symptoms. [[Gerolamo Cardano]] and [[Giambattista della Porta]] believed polluted water and fumes caused the symptoms of hysteria. Towards the end of the century, the role of the uterus was no longer thought central to the disorder, with [[Thomas Willis]] discovering that the brain and central nervous system were the cause of the symptoms. [[Thomas Sydenham]] argued that the symptoms of hysteria may have an organic cause. He also proved the uterus is not the cause of symptoms.<ref name="Tasca 110–119"/>

In 1692, in the U.S. town of [[Salem, Massachusetts]], there was a reported outbreak of hysteria. This led to the [[Salem witch trials]], where women who were accused of being witches had symptoms such as sudden movements, staring eyes, and uncontrollable jumping.<ref name="Tasca 110–119"/>

During the 18th century, there was a move from the idea of hysteria being caused by the uterus to it being caused by the brain. This led to an understanding that it could affect both sexes. [[Jean-Martin Charcot]] argued that hysteria was caused by "a hereditary degeneration of the nervous system, namely a neurological disorder".<ref name="Tasca 110–119"/>

In the 19th century, hysteria moved from being considered a neurological disorder to being considered a psychological disorder, when [[Pierre Janet]] argued that "dissociation appears autonomously for neurotic reasons, and in such a way as to adversely disturb the individual's everyday life".<ref name="Tasca 110–119"/> As early as 1874, doctors including [[William Benjamin Carpenter|W. B. Carpenter]] and J. A. Omerod began to speak out against the hysteria phenomenon as there was no evidence to prove its existence.<ref name="Webster">{{Cite web| url = http://www.richardwebster.net/freudandcharcot.html| archive-url = https://web.archive.org/web/20040511073634/http://www.richardwebster.net/freudandcharcot.html| url-status = usurped| archive-date = May 11, 2004| title = The hysteria diagnosis: Freud, Charcot, Breuer and Anna O| last = Webster| first = Richard| website = www.richardwebster.net| access-date = 2016-02-29}}</ref>

[[Sigmund Freud]] referred to the condition as both hysteria and conversion disorder throughout his career. He believed those with the condition could not live in a mature relationship, and that those with the condition were unwell in order to achieve a "secondary gain", in that they are able to manipulate their situation to fit their needs or desires. He also found that both men and women could have the disorder.<ref name="Tasca 110–119"/>

Freud's model<ref name="ReferenceA">Josef Breuer & Sigmund Freud, ''Studies in Hysteria'', 1895</ref> suggested the emotional charge deriving from painful experiences would be consciously repressed as a way of managing the pain, but that the emotional charge would be somehow "converted" into neurological symptoms. Freud later argued that the repressed experiences were of a sexual nature.<ref>{{cite book | author = Freud S | title = Fragment of an analysis of a case of hysteria. | year = 1905}}</ref> As Peter Halligan comments, conversion has "the doubtful distinction among psychiatric diagnoses of still invoking Freudian mechanisms".<ref name="pmid10834873">{{cite journal |vauthors=Halligan PW, Bass C, Wade DT | title = New approaches to conversion hysteria | journal = BMJ | volume = 320 | issue = 7248 | pages = 1488–9 | year = 2000 | pmid = 10834873 | pmc = 1118088 | doi = 10.1136/bmj.320.7248.1488}}</ref>

[[Pierre Janet]], a highly noted psychologist during the early 20th century, argued that symptoms arose through the power of suggestion, acting on a personality vulnerable to [[dissociation (psychology)|dissociation]].<ref>{{cite book | author = Janet P | title = The Major Symptoms of Hysteria | year = 1920 | edition = 2nd }}</ref> In this hypothetical process, the subject's experience of their leg, for example, is split off from the rest of their consciousness, resulting in paralysis or numbness in that leg.

Some support for the Freudian model comes from findings of high rates of childhood sexual abuse in conversion patients.<ref name="pmid12411227">{{cite journal |vauthors=Roelofs K, Keijsers GP, Hoogduin KA, Näring GW, Moene FC | s2cid = 24809182 | title = Childhood abuse in patients with conversion disorder | journal = Am J Psychiatry | volume = 159 | issue = 11 | pages = 1908–13 | year = 2002 | pmid = 12411227 | doi = 10.1176/appi.ajp.159.11.1908| hdl = 1887/14240 | url = https://repository.ubn.ru.nl//bitstream/handle/2066/62161/62161.pdf | hdl-access = free }}</ref> Support for the dissociation model comes from studies showing heightened suggestibility in patients with conversion disorder.<ref name="pmid12003460">{{cite journal |vauthors=Roelofs K, Hoogduin KA, Keijsers GP, Näring GW, Moene FC, Sandijck P | title = Hypnotic susceptibility in patients with conversion disorder | journal = J Abnorm Psychol | volume = 111 | issue = 2 | pages = 390–5 | year = 2002 | pmid = 12003460 | doi = 10.1037/0021-843x.111.2.390| hdl = 1887/14289 | s2cid = 31958662 | url = https://repository.ubn.ru.nl//bitstream/handle/2066/62234/62234.pdf | hdl-access = free }}</ref> Critics argue that it can be challenging to find organic pathologies for all symptoms, and so the practice of diagnosing patients with such symptoms as having hysteria led to the disorder being meaningless, vague and a sham diagnosis, as it does not refer to any definable disease.<ref name=":44">{{Cite web |last=Webster |first=Richard |title=Sigmund Freud: hysteria, somatization, medicine and misdiagnosis |url=http://www.richardwebster.net/freudandhysteria.html |url-status=usurped |archive-url=https://web.archive.org/web/20040511073728/http://www.richardwebster.net/freudandhysteria.html |archive-date=May 11, 2004 |access-date=2016-02-21 |website=www.richardwebster.net}}</ref> 

Throughout its history, many patients have been misdiagnosed with hysteria or conversion disorder when they had organic disorders such as [[Neoplasm|tumors]], [[epilepsy]], or [[vascular diseases]]. This has led to patient deaths, a lack of appropriate care, and suffering for the patients.<ref name=":44" />

[[Eliot Slater]], after studying the condition in the 1950s, stated: "The diagnosis of 'hysteria' is all too often a way of avoiding a confrontation with our own ignorance. This is especially dangerous when there is an underlying organic pathology, not yet recognised. In this penumbra we find patients who know themselves to be ill but, coming up against the blank faces of doctors who refuse to believe in the reality of their illness, proceed by way of emotional lability, overstatement and demands for attention{{nbsp}}... Here is an area where catastrophic errors can be made. In fact it is often possible to recognise the presence though not the nature of the unrecognisable, to know that a man must be ill or in pain when all the tests are negative. But it is only possible to those who come to their task in a spirit of humility. In the main the diagnosis of 'hysteria' applies to a disorder of the doctor–patient relationship. It is evidence of non-communication, of a mutual misunderstanding{{nbsp}}... We are, often, unwilling to tell the full truth or to admit to ignorance{{nbsp}}... Evasions, even untruths, on the doctor's side are among the most powerful and frequently used methods he has for bringing about an efflorescence of 'hysteria'".<ref name=":44"/>

The onset of conversion disorder often correlates to a traumatic or stressful event. There are certain populations that are considered at risk for conversion disorder, including people with a medical illness or condition, people with [[personality disorder]]s or [[dissociative disorders]].<ref name="National Institute of Health, 2012"/> No [[biomarker]]s have yet been found to support the idea that conversion disorder is caused by a psychiatric condition.

There has been much recent interest in using [[functional neuroimaging]] to study conversion. As researchers identify the mechanisms which underlie conversion symptoms, it is hoped they will enable the development of a [[Neuropsychology|neuropsychological]] model. A number of such studies have been performed, including some which suggest the blood-flow in patients' brains may be abnormal while they are unwell. The studies have all been too small to be confident of the generalisability of their findings, so no neuropsychological model has been clearly established.

An [[evolutionary psychology]] explanation for conversion disorder is that the symptoms may have been evolutionarily advantageous during warfare. A non-combatant with these symptoms signals non-verbally, possibly to someone speaking a different language, that she or he is not dangerous as a combatant and also may be carrying some form of dangerous [[infectious disease]]. This can explain that conversion disorder may develop following a threatening situation, that there may be a group effect with many people simultaneously developing similar symptoms, as in [[mass psychogenic illness]], and the gender difference in prevalence.<ref>{{cite journal | author = Bracha HS | title = Human brain evolution and the "Neuroevolutionary Time-depth Principle:" Implications for the Reclassification of fear-circuitry-related traits in DSM-V and for studying resilience to warzone-related posttraumatic stress disorder | journal = Progress in Neuro-Psychopharmacology and Biological Psychiatry | volume = 30 | issue = 5 | pages = 827–853 | year = 2006 | pmid = 16563589 | pmc = 7130737| doi = 10.1016/j.pnpbp.2006.01.008 | url = http://cogprints.org/5013/1/2006_P.N.P._Neuro-evolution_of_fear_circuit_disorders.pdf }}</ref>

==See also==
* [[Body-centred countertransference]]
* [[Functional neurologic disorder]] (FND)
* [[Post-traumatic stress disorder]] (PTSD) and [[Complex post-traumatic stress disorder]] (C-PTSD)
* [[Somatic symptom disorder]]
* [[Functional disorder]]

==References==

{{reflist|30em}}

==External links==

{{Medical resources
| DiseasesDB      = 1645
| ICD10           = {{ICD10|F|44||f|40}}
| ICD9            = {{ICD9|300.11}}
| ICDO            = 
| OMIM            = 
| MedlinePlus     = 000954
| eMedicineSubj   = emerg
| eMedicineTopic  = 112
| eMedicine_mult  = {{eMedicine2|med|1150}}
| MeshID          = D003291
}}

{{Mental and behavioral disorders|neurotic}}

[[Category:Disorders causing seizures]]
[[Category:Mass psychogenic illness]]
[[Category:Somatic symptom disorders]]