Psychogenic movement disorders

All varieties of movement disorders may be mimicked by a psychogenic disorder, most commonly tremor, dystonia, and myoclonus. Approximately 3% of patients seen in specialty clinics have a psychogenic movement disorder (PMD). The diagnosis of a PMD depends on not just ruling out an organic movement disorder, but moreover, recognizing features from the history and examination that are inconsistent or incongruous with an organic movement disorder. Most PMDs represent a conversion disorder, sometimes as part of a somatoform disorder; less common diagnoses include a factitious disorder or malingering. Co-morbid psychiatric illness is prevalent in patients with PMD including depression, anxiety, and personality disorders. Many PMDs remain chronic, but a multidisciplinary approach centering on psychiatric intervention can be successful. A shorter duration of symptoms and a co-existent treatable psychiatric disorder portend a better prognosis, whereas compensation and pending litigation are associated with a poorer prognosis.