The term psychogenic dystonia refers to the uncommon but well-documented situation where dystonia is secondary to psychological disturbances.
Importantly, in all but the most unusual cases, the process is completely subconscious. The individual is not consciously aware of causing the abnormal movements. (The term used to describe individuals who purposefully cause movements for some type of gain is known as “malingering” and is not considered a medical disorder.)
Psychogenic dystonia may closely resemble “organic” (i.e. non-psychogenic) dystonias, and in most cases only an experienced movement disorder expert can identify the subtle aspects of an individual’s history and physical examination that support a psychogenic cause for the symptoms.
Psychogenic dystonia can be extremely disabling with impairment affecting all normal daily activities and even self-care tasks. Therefore, the severity of dystonia and disability that it causes is not helpful in differentiating between psychogenic and non-psychogenic dystonia. Nor is the duration of the problem useful. Some cases of psychogenic dystonia become chronic or sustained lasting many years.
Psychogenic dystonia is considered a form of “conversion disorder.” By this we mean that psychological/psychiatric dysfunction causes physical signs and symptoms. Exactly how and why this occurs is not well understood. It is increasingly recognized that disturbances of brain function do underlie the occurrence of neurological conversion symptoms.
The underlying psychiatric disturbance varies from patient to patient. Depression and anxiety have been found to be common in such patients and many of these patients have more than one primary psychiatric problem as well as additional underlying personality disorders. Defining the presence and nature of these problems is also sometimes difficult.
The diagnosis of psychogenic dystonia can be exceedingly difficult. It is complicated by the long and unfortunate history of patients with true organic forms of dystonia being misdiagnosed with psychiatric illness. Secondary dystonias and psychogenic dystonias, in particular, may have similar characteristics. Plus, it is believed that, while rare, psychogenic dystonia is under-diagnosed.
Movement disorder experts recognize examples of psychogenic causes for almost all types of abnormal movement. Cases of psychogenic dystonia may account for less than 3% of all dystonia patients.
Given the complexities of the diagnosis of dystonia in general, the diagnosis of psychogenic dystonia can only be made by a physician with considerable experience in the field of dystonia and other abnormal movement disorders, often working in partnership with a psychiatric expert in conversion disorders. Patients must be evaluated several times or over a prolonged period before a definitive diagnosis of psychogenic dystonia can be made. A single psychiatric interview is not sufficient to demonstrate the underlying psychiatric dysfunction. Additionally, the presence of overt psychiatric illness in an individual with dystonia is not necessarily support for a “psychogenic” diagnosis. The association may be coincidental or the disability and physical disturbances caused by dystonia can result in psychiatric dysfunction such as depression. Other causes of dystonia must be considered and appropriately excluded using a variety of investigations.
It is important that psychogenic dystonia is diagnosed correctly since these patients require treatment directed towards the underlying causative psychiatric problems rather than to the dystonic manifestations (although physical therapy can be helpful for both). Trials of medications used to treat organic dystonia will not provide sustained benefit and could be harmful. The best course of treatment may be a combination of medication and psychotherapy under the care of a team of professional, for example a movement disorder expert, a psychiatrist, and a counselor who specializes in cognitive-behavior techniques.
There is a clear need for more research directed at defining better and more accurate methods of diagnosis and establishing more effective treatment guidelines and methods.