Conversion disorder

Conversion disorder is a condition in which a person has physical symptoms, but with no physical cause. People with conversion disorder may lose their sight or hearing, become paralysed (unable to move), or display a number of other symptoms that involve the nervous system.

Conversion disorder is not common. It is estimated to occur in 2-5 of every 100,000 people. About 5-15% of people referred to neurology clinics are diagnosed with conversion disorder.

People with conversion disorder are not 'faking' - their symptoms are genuine, and they experience the same degree of disability as any other person with a disability. If a person is consciously faking illness, this is not conversion disorder but either factitious disorder (Münchausen syndrome), where a person pretends to have an illness for the sake of being considered ill, or malingering (where a person fakes illness for personal gain).

Causes

Conversion disorder was known as 'hysteria' until 1968, and many explanations had been offered over the ages for its appearance. It is still not understood what causes this disorder; it may be the result of psychological or neurological factors, or a combination of the two.

The symptoms are often triggered by a stressful event - it may be that conversion disorder is a way for the brain to cope with stress by 'channelling' the emotional stress into physical symptoms.

Signs and symptoms

People with conversion disorder display one or more of the following symptoms:

• Vision loss or other vision difficulties (double vision, tunnel vision);
• Hearing loss or other hearing difficulties;
• Loss of sense of smell, touch or pain;
• Weakness or paralysis;
• Seizures, tremors;
• Inability to urinate (pee);
• Difficulty swallowing;
• Difficulty speaking;
• Problems with balance, walking, coordination, and;
• In some people, La belle indifférence - a lack of distress regarding their symptoms.

Methods for diagnosis

Since the causes are not known and have much to do with the person's mental state, diagnosis of conversion disorder is not easy and not always accurate. Also, conversion disorder can occur along with neurological conditions, making diagnosis a difficult task.

The doctor will first try to find a physical explanation for the symptoms and will perform the appropriate examinations and tests. If no good alternative explanation is found and the person exhibits some of the risk factors listed above, the doctor may suspect conversion disorder.

A further complication of diagnosis is that in conversion disorder, the more the doctor investigates, the longer the patient's symptoms may continue.

Recent brain imaging studies suggest that in conversion disorder, the limbic system (the area of the brain responsible for emotion, among other things) influences or overrides the motor and sensory areas of the brain. These are, however, only preliminary results.

Types of treatment

Treatment of conversion disorder is through psychotherapy (cognitive behaviour therapy), often in combination with physiotherapy and stress management techniques. Explaining the diagnosis to the person and reassuring them can also help. For people who also have another mental health condition, treating this disorder can also help relieve the symptoms of conversion disorder.

Trust is important. Placebo treatments, and other 'non-treatments' designed to mislead the person into thinking they are receiving treatment, are not recommended. They may impair trust between doctor and patient and sabotage future treatment efforts. That said, some researchers argue that there is a place for such measures in treatment.

Transcranial magnetic stimulation, which uses a focused magnetic field to activate specific areas of the brain, is a suggested technique for treating conversion disorder. Trials show promise, but the therapy is still not in general use.

Psychotherapy can help with the management of conversion disorder. 

Prognosis

For some, an episode of conversion disorder is temporary and can last for any length of time, from minutes to days or weeks. Episodes can recur; 20-25% of people who have had an episode of conversion disorder will experience another one within a year.

For others, an episode of conversion disorder is an ongoing affliction that can last many years. This is more common in people who suffer from other mental disorders.