Conversion disorder: Wikis

  

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Conversion disorder
Classification and external resources
ICD-10 F44.
ICD-9 300.11
DiseasesDB 1645
eMedicine emerg/112 med/1150
MeSH D003291

Conversion disorder is a condition where patients present with neurological symptoms such as numbness, paralysis, or fits, but where no neurological explanation can be found. It is thought that these problems arise in response to difficulties in the patient's life, and conversion is considered a psychiatric disorder in the International Statistical Classification of Diseases and Related Health Problems (ICD-10)[1] and Diagnostic and Statistical Manual of Mental Disorders 4th edition (DSM-IV).[2] Formerly known as "hysteria", the disorder has arguably been known for millennia, though it came to greatest prominence at the end of the 19th century, when the neurologist Jean-Martin Charcot, and psychiatrists Pierre Janet and Sigmund Freud made it the focus of their study. The term "conversion" has its origins in Freud's doctrine that anxiety is "converted" into physical symptoms.[3] Though previously thought to have vanished from the west in the 20th century, some research has suggested it is as common as ever.[4]

Contents

Definition

DSM-IV defines conversion disorder as follows:

  • One or more symptoms or deficits are present that affect voluntary motor or sensory function suggestive of a neurologic or other general medical condition.
  • Psychological factors are judged, in the clinician's belief, to be associated with the symptom or deficit because conflicts or other stressors precede the initiation or exacerbation of the symptom or deficit. A diagnosis where the stressor precedes the onset of symptoms by up to 15 years is not unusual.
  • The symptom or deficit, after appropriate investigation, cannot be explained fully by a general medical condition, the direct effects of a substance, or as a culturally sanctioned behavior or experience.
  • The symptom or deficit causes clinically significant distress or impairment in social, occupational, or other important areas of functioning or warrants medical evaluation.

The nature of the association between the psychological factors and the neurological symptoms remains unclear. Earlier versions of the DSM-IV employed psychodynamic concepts, but these have been incrementally removed from successive versions. The ICD-10 classifies conversion disorder as dissociative (conversion) disorder, which suggests the symptoms arise through the process of dissociation.

History

In the 19th century, physicians such as Silas Weir Mitchell in the US and Paul Briquet and Jean-Martin Charcot in France developed ideas about patients sharing unexplained neurological symptoms. Charcot specialised in treating patients who were suffering from a variety of unexplained physical symptoms including paralysis, contractures (muscles which contract and cannot be relaxed) and seizures. Some of these patients sporadically and compulsively adopted a bizarre posture (christened arc-de-cercle) in which they arched their body backwards until they were supported only by their head and their heels.

The term "Conversion disorder" originated with Freud. He viewed these apparently neurological symptoms as a result of the conversion of intrapsychic distress in to physical symptoms. The affected body part was seen as a symbolic infantile sex organ. Irrational panic is always the result of sexual deprivation, and conversion is a reaction—an acceptable alternative—to the intolerable anxiety in panic. This distress was thought to cause the brain to unconsciously disable or impair a bodily function as a side effect of the original repression, which served to relieve the patient's anxiety.[5] However, recent evidence suggests that patients do remain distressed by their symptoms in the long term[6] It has also been suggested that at least some of the classic psychoanalytic cases of hysteria, such as "Anna O.",[7] may actually have suffered from organic illness.

Presentation

Conversion disorder can present with any motor or sensory symptom including any of the following:

Diagnosis

The diagnosis of conversion disorder involves three elements: the exclusion of neurological disease, the exclusion of feigning, and the determination of a psychological mechanism. Each of these has difficulties.

Exclusion of neurological disease

Conversion disorder presents with symptoms that typically resemble a neurological disorder such as stroke, multiple sclerosis, or epilepsy. The neurologist must carefully exclude neurological disease, through examination and appropriate investigations.[8] However, it is not uncommon for patients with neurological disease to also have conversion disorder,[9] in which case the task becomes to determine how much of the patient's problem is due to conversion.

In excluding neurological disease, the neurologist has traditionally relied partly on the presence of positive signs of conversion disorder — certain aspects of the presentation that were thought to be rare in neurological disease, but common in conversion. The validity of many of these signs has been questioned, however, by a study showing that they also occurred in neurological disease.[10] 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 later study no evidence was found that patients with "functional" symptoms are any more likely to exhibit this than patients with a confirmed organic disease.[11] Another feature thought to be important was that symptoms would tend to be more severe on the non-dominant (usually left) side; there were a variety of theories such as the relative involvement of cerebral hemispheres in emotional processing, or more simply just 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.[12]

The process of exclusion is not perfect, so misdiagnoses will occur. However, in a highly influential[13] study from the 1960s, Eliot Slater demonstrated that misdiagnoses had occurred in one third of his 112 patients with conversion disorder.[14] Later authors have argued that the paper was flawed, however,[15][16] and a meta-analysis has shown that misdiagnosis rates since that paper are around 4%, the same as for other neurological diseases.[17]

Exclusion of feigning

Conversion disorder is unique in DSM-IV in explicitly requiring the exclusion of deliberate feigning. Unfortunately, this is only likely to be demonstrable where the patient confesses, or is "caught out" in a broader deception, such as a false identity.[18] One neuroimaging study suggested that feigning may be distinguished from conversion by the pattern of frontal lobe activation;[19] however this is a research, rather than a clinical technique. True rates of feigning in medicine remain unknown, though neurological presentations of feigning may be among the more common.[20]

Establishing a psychological mechanism

The psychological mechanism can be the most difficult aspect of the conversion diagnosis. DSM-IV requires that the clinician believe preceding stressors or conflicts to be associated with the development of the disorder, though how this might come about is still the subject of debate. The original Freudian model[21] suggested that the emotional charge of painful experiences would be consciously repressed as a way of managing the pain, but this emotional charge would be somehow "converted" into the neurological symptoms. Freud later argued that the repressed experiences were of a sexual nature.[22] As Peter Halligan comments, conversion has 'the doubtful distinction among psychiatric diagnoses of still invoking Freudian mechanisms'[23] Janet, the other great theoretician of hysteria, argued that symptoms arose through the power of suggestion, acting on a personality vulnerable to dissociation.[24] 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. Later authors have attempted to combine elements of these models, but none of them has a firm empirical basis.[25] Some support for the Freudian model comes from findings of high rates of childhood sexual abuse in conversion patients[26] and from a recent neuroimaging study showing abnormal emotion processing of a traumatic event linked to motor processing of the affected limb, in a patient with conversion.[27] Support for the dissociation model comes from studies showing heightened suggestibility in conversion patients,[28] and in abnormalities in motor imagery.[29] There has been much recent interest in functional neuroimaging in conversion. As researchers identify the mechanisms which underlie conversion symptoms it is hoped these will allow the development of a neuropsychological model. A number of such studies have been performed, including some which suggest that blood flow in patients brains may be abnormal while they are unwell. These have all been too small to be confident of the generalisability of their findings, however, so no neuropsychological model has been clearly established.

Epidemiology

Prevalence

Information on the prevalence of conversion disorder in the West is limited, in part due to the complexities of the diagnostic process. In neurological settings, rates of unexplained symptoms are very high, at between 30 and 60%,[30][31][32] which suggests conversion to be more common than most neurological diseases. However, the diagnosis of conversion typically requires an additional psychiatric evaluation, yet few patients will see a psychiatrist[33] so an unknown fraction of those unexplained symptoms will be due to conversion. Large scale psychiatric registers in the US and Iceland found rates of 22 and 11 per 100000 per year, respectively,[34] but it is unclear what proportion of unexplained symptoms these represent.

Culture

It is often thought that rates are higher outside of the West, perhaps related to cultural and medical attitudes, though evidence for this is again limited.[35] A community survey of urban Turkey found a rate of 5.6%.[36] Many authors have found rates to be higher in rural and lower socio-economic groups where technological investigation of patients is limited.[37][38][39]

Gender

'Hysteria' was originally understood to be a condition exclusively affecting women, though it has increasingly been recognised in men. In recent, larger studies,[40][41] women continue to predominate, with between 2 and 6 female patients for every male.

Age

Conversion disorder may present at any age but is rare in children younger than 10 years or in the elderly. Studies suggest a peak onset in the mid-to-late 30s.[42][43][44]

Treatment

Treatment may include the following:[45]

  1. Explanation. This must be clear and coherent as attributing physical symptoms to a psychological cause is not accepted by many educated people in western cultures. It must emphasise the genuineness of the condition, that it is common, potentially reversible and does not mean that the sufferer is a "psycho". Taking an aetiologically neutral stance by describing the symptoms as functional may be helpful but further studies are required. Ideally the patient should be followed up neurologically for a while to ensure that the diagnosis has been understood.
  2. Physiotherapy where appropriate;
  3. Treatment of comorbid depression or anxiety if present.

There is little evidence-based treatment of conversion disorder.[46] Other treatments such as cognitive behavioral therapy, hypnosis, EMDR, and psychodynamic psychotherapy need further trials.

References

  1. ^ The ICD-10 classification of mental and behavioural disorders: clinical descriptions and diagnostic guidelines. Geneva, World Health Organization, 1992
  2. ^ Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, American Psychiatric Association
  3. ^ Josef Breuer & Sigmund Freud, "Studies in Hysteria", 1895
  4. ^ 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.
  5. ^ Breuer and Freud, "Studies in Hysteria", 1895
  6. ^ Stone, et al., JR Soc Med 2005; 98:547–548
  7. ^ Alison Orr-Andrewes, "The case of Anna O: A Neuropsychiatric perspective", Journal of the Psychoanalytic Association 1987, vol 35 p.399.
  8. ^ Stone J, Carson A, Sharpe M., 2005, Functional symptoms in neurology: Assessment, Journal of Neurology, Neurosurgery and Psychiatry (Neurology in Practice); 76 (Suppl 1): 2–12
  9. ^ Eames P, 1992, "Hysteria following brain injury", Journal of Neurology, Neurosurgery, and Psychiatry, Vol 55, 1046–1053
  10. ^ Gould R, Miller B L, Goldberg M A, Benson D F, 1986, The validity of hysterical signs and symptoms, The Journal of nervous and mental disease, vol. 174, no10, pp. 593–597
  11. ^ Stone J, Smyth R, Carson A, Warlow C, Sharpe M., "La belle indifference in conversion symptoms and hysteria: systematic review." Br J Psychiatry. 2006 Mar;188 pp. 204–9.
  12. ^ Stone J, Sharpe M, Carson A, Lewis SC, Thomas B, Goldbeck R, Warlow CP. "Are functional motor and sensory symptoms really more frequent on the left? A systematic review." J Neurol Neurosurg Psychiatry. 2002 Nov;73(5) pp. 578–81.
  13. ^ Slater, E. "Diagnosis of Hysteria"Br Med J 1965 May; 1 pp. 1395–99.
  14. ^ Slater ET, Glithero E. "A follow-up of patients diagnosed as suffering from "hysteria" J Psychosom Res 1965 Sep;9(1) pp. 9–13.
  15. ^ 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.
  16. ^ Stone, et al., JR Soc Med 2005; 98:547–548
  17. ^ Stone, et al., BMJ 2005
  18. ^ Krahn L, Hongzhe L, O'Connor K. "Patients who strive to be ill: Factitious disorder with physical symptoms." American Journal of Psychiatry, 2003; 160(6), pp. 1163–8.
  19. ^ Spence SA, Crimlisk HL, Cope H, Ron MA, Grasby PM. "Discrete neurophsyiological correlates in prefrontal cortex during hysterical and feigned disorder of movement." Lancet 2000 Apr 8; 355(9211), pp. 1243–4.
  20. ^ Eckhardt A, "Factitious disorders in the field of neurology and psychiatry." 1994; 62(1–2), pp. 56–62.
  21. ^ Josef Breuer & Sigmund Freud, "Studies in Hysteria", 1895
  22. ^ Freud S, "Dora: Fragment of an analysis of a case of hysteria.", 1905
  23. ^ 'New approaches to conversion hysteria, Peter W Halligan, Christopher Bass, Derick T Wade, BMJ 2000; 320:1488–1489, 3 June.
  24. ^ Janet, P. "The Major Symptoms of Hysteria", 1920, 2nd Edition
  25. ^ Brown, RJ. "Psychological mechanisms of medically unexplained symptoms: an integrative conceptual model." Psychol Bull. 2004 Sep;130(5):793–812.
  26. ^ Roelofs K, Keijsers GP, Hoogduin KA, Näring GW, Moene FC., "Childhood abuse in patients with conversion disorder." Am J Psychiatry. 2002 Nov;159(11):1908–13.
  27. ^ Kanaan RA, Craig TK, Wessely SC, David AS. "Imaging repressed memories in motor conversion disorder." Psychosom Med. 2007 Feb–Mar;69(2):202–5.
  28. ^ Roelofs K, Hoogduin KA, Keijsers GP, Näring GW, Moene FC, Sandijck P. "Hypnotic susceptibility in patients with conversion disorder." J Abnorm Psychol. 2002 May;111(2):390–5.
  29. ^ Roelofs K, van Galen GP, Keijsers GP, Hoogduin CA. "Motor initiation and execution in patients with conversion paralysis." Acta Psychol (Amst). 2002 May;110(1):21–34.
  30. ^ Carson AJ, Ringbauer B, Stone J, McKenzie L, Warlow C, Sharpe M. "Do medically unexplained symptoms matter? A prospective cohort study of 300 new referrals to neurology outpatient clinics." J Neurol Neurosurg Psychiatry. 2000 Feb;68(2):207–10.
  31. ^ Nimnuan C, Hotopf M, Wessely S. "Medically unexplained symptoms: an epidemiological study in seven specialities." J Psychosom Res. 2001 Jul;51(1):361–7.
  32. ^ Snijders TJ, de Leeuw FE, Klumpers UM, Kappelle LJ, van Gijn J. "Prevalence and predictors of unexplained neurological symptoms in an academic neurology outpatient clinic--an observational study." J Neurol. 2004 Jan;251(1):66–71.
  33. ^ Crimlisk HL, Bhatia KP, Cope H, David AS, Marsden D, Ron MA. "Patterns of referral in patients with medically unexplained motor symptoms." J Psychosom Res. 2000 Sep;49(3):217–9.
  34. ^ Stefánsson JG, Messina JA, Meyerowitz S. "Hysterical neurosis, conversion type: clinical and epidemiological considerations." Acta Psychiatrica Scandinavica 1976 Feb;53(2):119–38.
  35. ^ 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.
  36. ^ Deveci A, Taskin O, Dinc G, Yilmaz H, Demet MM, Erbay-Dundar P, Kaya E, Ozmen E. "Prevalence of pseudoneurologic conversion disorder in an urban community in Manisa, Turkey." Soc Psychiatry Psychiatr Epidemiol. 2007 Nov;42(11):857–64.
  37. ^ Stefánsson JG, Messina JA, Meyerowitz S. "Hysterical neurosis, conversion type: clinical and epidemiological considerations." Acta Psychiatrica Scandinavica 1976 Feb;53(2):119–38.
  38. ^ Tomasson K, Kent D, Coryell W. "Somatization and conversion disorders: comorbidity and demographics at presentation." Acta Psychiatrica Scandinavica 1991 Sep;84(3):288–93.
  39. ^ Kuloglu M, Atmaca M, Tezcan E, Gecici O, Bulut S. "Sociodemographic and clinical characteristics of patients with conversion disorder in Eastern Turkey." Soc Psychiatry Psychiatr Epidemiol. 2003 Feb;38(2):88–93.
  40. ^ Deveci A, Taskin O, Dinc G, Yilmaz H, Demet MM, Erbay-Dundar P, Kaya E, Ozmen E. "Prevalence of pseudoneurologic conversion disorder in an urban community in Manisa, Turkey." Soc Psychiatry Psychiatr Epidemiol. 2007 Nov;42(11):857–64.
  41. ^ Carson AJ, Ringbauer B, Stone J, McKenzie L, Warlow C, Sharpe M. "Do medically unexplained symptoms matter? A prospective cohort study of 300 new referrals to neurology outpatient clinics." J Neurol Neurosurg Psychiatry. 2000 Feb;68(2):207–10.
  42. ^ Carson AJ, Ringbauer B, Stone J, McKenzie L, Warlow C, Sharpe M. "Do medically unexplained symptoms matter? A prospective cohort study of 300 new referrals to neurology outpatient clinics." J Neurol Neurosurg Psychiatry. 2000 Feb;68(2):207–10.
  43. ^ Stefánsson JG, Messina JA, Meyerowitz S. "Hysterical neurosis, conversion type: clinical and epidemiological considerations." Acta Psychiatrica Scandinavica 1976 Feb;53(2):119–38.
  44. ^ Deveci A, Taskin O, Dinc G, Yilmaz H, Demet MM, Erbay-Dundar P, Kaya E, Ozmen E. "Prevalence of pseudoneurologic conversion disorder in an urban community in Manisa, Turkey." Soc Psychiatry Psychiatr Epidemiol. 2007 Nov;42(11):857–64.
  45. ^ Stone J, Carson A, Sharpe M. "Functional symptoms in neurology: management." J Neurol Neurosurg Psychiatry. 2005 Mar;76 Suppl 1:i13–21.
  46. ^ Ruddy and House, Cochrane Collaboration







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