Conversion disorder: History of the disorder

History
There has been a long history of symptoms without any underlying physical cause. In women, the term Female hysteria was used to refer to a wide spectrum of symptoms ranging from fainting to anxiety. As a term it goes back over 2000 years and was thought to relate to abnormal motions of the uterus. From the 17th century onwards, Thomas Willis, Robert Whytt and others increasingly realised the problem was in fact localised to the brain and mind.

In the 19th century, physicians such as Weir Mitchell in the US and Briquet and Jean-Martin Charcot in France developed increasingly sophisticated ideas about patients with these neurological symptoms which would now be classed as neuropsychiatric. They developed complex aetiological models which incorporated biological, psychological and social factors and distinguished general predisposition from the mechanism of the symptom. In the 20th Century, Freudian psychodynamic ideas were prevalent.

The term "Conversion disorder" is a legacy of Freud and the psychotherapy movement. He viewed these apparently neurological symptoms as a result of the conversion of intrapsychic distress in to physical symptoms. It is worth bearing in mind that much of Freud's work is now viewed with scepticism, and it may be that patients Freud thought were hysterical may actually have suffered from organic illness, such as "Anna O." (see Alison Orr-Andrewes, "The case of Anna O: A Neuropsychiatric perspective" in Journal of the Psychoanalytic Association 1987, vol 35 p.399).

In the 1960s the London Psychiatrist Eliot Slater recognised that finding a life event just before the onset of a symptom was an entirely unreliable way of diagnosing conversion disorder “Unfortunately we have to recognise that trouble, discord, anxiety and frustration are so prevalent at all stages of life that their mere occurrence near to the time of onset of an illness does not mean very much”- Eliot Slater

He also suggested that conversion disorder was largely a 'delusion and a snare' since many of the people said to have it would eventually go on to develop a neurological disease that in hindsight could explain their original symptoms

Studies since 1970 have shown that misdiagnosis still occurs but at a rate of around 5% which is the same as for other neurological and pscyhiatric symptoms (Stone et al BMJ 2005).

Historically Conversion disorder was thought to manifest itself in many different ways. Conversion disorders were thought to be triggered by acute psychosocial stress that the individual could not process psychologically. This overwhelming distress was thought to cause the brain to unconsciously disable or impair a bodily function which would relieve or prevent the patient from experiencing this stressor again. This is in stark contrast to the modern understanding that patients remain distressed by their symptoms in the long term (Stone et al JR Soc Med 2005; 98:547-548) and generally any hypothesised stressor is removed temporally and symbolically from the onset of symptoms. Therefore, the psychosocial stress cannot be seen to be "converted' into a physical symptom that relieve suffering, when in actual fact they increase it. Historically The patient, by definition, was considered to be unaware of this process, and often not concerned with his deficit--- a feature called 'la belle indifference'. Research now shows this to be untrue (Stone et al as above).

More recently, research is attempting to examine the complex nature of these symptoms and the absurdity of a dualist approach which attempts to suggest that symptoms are either all organic or all psychiatric. Functional neuroimaging has shown intriguing findings with respect to the neural correlates of these symptoms (best example is Vuilleimier et al Brain Vol. 124, No. 6, 1077-1090, June 2001)