Conversion disorder
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Definition
Conversion Disorder is a DSM-IV diagnosis which describes neurological symptoms such as weakness, sensory disturbance and attacks that look like epilepsy but which can not be attributed to a known neurological disease.
The DSM-IV definition, which is by no means agreed upon by all those working in the field, is 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 to be associated with the symptom or deficit because conflicts or other stressors precede the initiation or exacerbation of the symptom or deficit.
- The symptom or deficit is not intentionally produced or feigned (as in factitious disorder or malingering).
- 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 symptom or deficit is not limited to pain or sexual dysfunction, does not occur exclusively during the course of somatization disorder, and is not better accounted for by another mental disorder.
The condition has a complex history. These symptoms are also described as functional, non-organic, hysterical, psychogenic, depending on your aetiological point of view. In the International Classification of Diseases they are termed Dissociative. Some individuals choose to use the term Functional Neurological Deficit which research has shown to be a more acceptable term in doctor patient relationships (Stone et al).
That there should be a temporal relationship between symptom onset and some external event of psychological conflict is a question of debate:
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)
Diagnosis
Conversion disorder can present with any motor or sensory symptom in the body including:
- Weakness / Paralysis of a limb or the entire body hysterical paralysis or motor conversion disorders
- Impaired hearing or vision
- Loss / Disturbance of sensation
- Impairment or loss of speech--- hysterical aphonia
- Psychogenic non-epileptic seizures
- Fixed Dystonia unlike normal dystonia
- Tremor, Myoclonus or other movement disorders
- Astasia-abasia or Gait Problems
Diagnosis depends not on the absence of findings of neurological disease but on the finding of positive evidence of conversion symptoms.
Conversion symptoms are remarkably consistent between patients, just as Parkinson's disease is consistent between patients. There may be positive evidence of patterns of weakness (for example Hoover's Sign or a non-pyramidal pattern of weakness) or a typical gait problem (for example a 'dragging monoplegic gait). For Psychogenic non-epileptic seizures a range of features of the attacks must be taken in to consideration and the diagnosis may need confirmation with videotelemetry.
Diagnosis is not easy and should preferably only be made by a neurologist with experience of the condition.
Patients with conversion symptoms will typically have multiple other symptoms which may include fatigue, sleep disturbance, memory and concentration difficulties, pain (neck, back, muscles), bowel and bladder sensitivity
Are people with conversion disorder malingering?
Often a patients reaction to the diagnosis of conversion disorder is to be offended that the doctor thinks they are crazy or making their symptoms up. It is true to say that many doctors still do regard these symptoms as 'not genuine' and not deserving of attention. However, many doctors do regard them as genuine but struggle to know how to communicate with patients
If patients with conversion symptoms were malingering there would be a number of problems from clinical practice to sort out:
- Evidence from long term studies showing that symptoms persist at follow up many years later
- Patients with conversion symptoms generally desire tests, malingerers would not
- There is remarkable consistency between patients (who have not met each other)
Treatment
Treatment may include the following
1. Explanation - This must be clear and coherent. 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 (Ruddy and House - Cochrane Collaboration). Other treatments such as cognitive behavioural therapy, hypnosis, psychodynamic psychotherapy need further trials.