We evaluated the natural history and prognosis of psychogenic or hysterical seizures in patients discharged from the Johns Hopkins Hospital in the 3 years between 1971 and 1974. Follow-up data were obtained 5 years or more after discharge. Among 41 patients with convincing evidence of psychogenic seizures, there were coexisting organic neurologic disorders in 18 (44%). Mental subnormality or retardation was present in 17% and true epileptic seizures in 37%. EEG abnormalities found in 38% of individuals with psychogenic seizures were attributed to these organic neurologic disorders or anticonvulsant drug toxicity. There was significant long-term morbidity in 56% of these individuals because of psychosocial problems rather than misdiagnosis of psychogenic seizures.