Psychogenic Movement Disorders

Psychogenic, psychosomatic, hysterical, or functional movement disorders are conditions related to an underlying psychiatric illness with no evidence of any organic etiology. One has to be very cautious. There is a major inherent difficulty whenever one entertains a diagnosis of a psychogenic movement disorder, because studies demonstrate that this is a too common and poorly documented diagnosis, in that up to 30% of patients diagnosed with psychogenic disorders eventually are found to have an organic neurologic illness. Because, with just a few exceptions, most movement disorders have no specific diagnostic laboratory or imaging study available, beyond clinical observation, there is a temptation by the uninitiated to label a patient hysterical when the clinician cannot arrive at a definitive organic diagnosis. An important diagnostic caveat is for the evaluating physician to not rush to judgment when the patient's findings do not initially fit a specific diagnostic set, such as pill-rolling rest tremor, cogwheel rigidity, masked facies, and en bloc walking as is typical of Parkinson disease. Astute clinicians often use a “tincture of time” to prospectively and carefully follow patients by repeated clinical evaluations. Here one monitors the individual patient for the gradual development of recognized classic signs of an evolving and well-recognized neurologic process. Barring the later clinical evolution of symptoms and findings into a more classic organic movement disorder, the clinician will gradually acquire information from the patient or family to become more comfortable with the importance of underlying psychogenic factors.

A variety of underlying psychiatric diagnoses are found in patients with psychogenic neurologic movement disorders; these include various somatoform and factitious disorders, malingering, depression, anxiety, and histrionic personality disorders. Although a specific psychiatric diagnosis cannot always be confirmed for these various abnormal and consistently inconsistent motor symptoms, despite the clinician's high suspicion of psychogenicity, an emotionally based diagnosis is not totally precluded. Often it is only time and a cautious diagnostic approach that will allow one to sort out the majority of these challenging patients’ specific diagnosis. In young women, one has to be particularly careful to not overlook sexual abuse, particularly incest.

Psychogenic tremor, dystonia, myoclonus, chorea, and parkinsonism are the typical means for a functional movement disorder to present and are particularly common in women ( Fig. 36.1 ). These patients usually have multiplicity and variability of symptoms superimposed on a significant psychiatric background. The neurologic findings do not fit a specific diagnostic set typical of the classic organic movement disorders. These factitious patients present with movements that are consistently inconsistent and are particularly liable to change or decrease during distraction. Frequently, patients with psychogenic movement disorders display uneconomic postures demonstrating a most exaggerated effort during examination that may also produce fatigue. They may demonstrate marked slowness when asked to perform certain tasks such as rapid alternating movements.

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Psychogenic Movement Disorder, Pseudochoreoathetosis.

Therapeutically, psychogenic movement disorders often respond to placebo or suggestion.