Psychogenic dystonia: a review of 18 cases.

OBJECTIVE To review the clinical characteristics and associated features found in patients with psychogenic dystonia. METHODS A 10 year retrospective chart review of all patients diagnosed by the author as having psychogenic dystonia. RESULTS Eighteen patients fulfilled diagnostic criteria for "Documented" or "Clinically Established" psychogenic dystonia. Clinical characteristics of the dystonia were inconsistent or incongruous with established forms of organic dystonia. Fourteen of the 18 patients had a known precipitant. In most, the onset was abrupt and progression occurred rapidly, often to fixed dystonic postures. In contrast to idiopathic dystonia, involvement of the legs was common (12 patients), despite onset in adult life. Although cases of isolated paroxysmal dystonia were excluded in the review, 10 patients had paroxysmal worsening of dystonia or other abnormal movements. Pain was a prominent feature in 14 of 16 patients with the complaint and 1 patient with documented psychogenic dystonia also had well established reflex sympathetic dystrophy (RSD). Other psychogenic movement disorders, psychogenic neurological signs and multiple somatizations were common. Long-term follow up was available for less than one-half of the patients. Outcome varied considerably; some patients had complete resolution of symptoms (including 1 who had undergone 2 previous thalamotomies) and others remained disabled by persistent dystonia. CONCLUSIONS Dystonia is uncommonly due to primary psychological factors. At times this is an extremely difficult diagnosis to make and even when the diagnosis is confirmed, management remains very challenging. Future studies are required in hopes of providing more efficient means of distinguishing psychogenic dystonia from other dystonic syndromes especially those which rarely follow peripheral injury or accompany RSD/causalgia syndromes.