The clinical presentations and criteria for diagnosis of psychogenic tremor in 24 patients are reported from the Department of Neurology, Kansas University Medical Center, Kansas City, KS. Two were adolescents and the remainder were adults; nine men and 15 women. The tremors were complex (resting, postural, and kinetic), and of abrupt onset with a variable course. The clinical characteristics included spontaneous remissions, clinical inconsistencies, changing tremors, unresponsiveness to drugs, exacerbation by attention, improvement with distractibi1ity, responsiveness to placebo, absence of other neurologic signs, and remission with psychotherapy. Other medical factors suggesting a psychogenic etiology included multiple undiagnosed conditions, unwitnessed paroxysmal disorders, employment in allied health professions, litigation or compensation pending, secondary gain, psychiatric disease, and functional disturbances in the past. 
COMMENT. Despite these clearly defined clinical features the diagnosis of psychogenic tremor is often difficult. Psychogenic and organic diseases may coexist and psychogenic tremor is usually a diagnosis of exclusion. In Pediatric Neurology practice, tremor is a frequent complication of valproate therapy for seizures and iatrogenic causes must be remembered in the differential diagnosis. The majority of patients with torsion dystonia in childhood are first diagnosed as hysteria. Acute dystonia is reported with cocaine withdrawal.