title: Cycloid psychosis: an investigation of the diagnostic concept.
abstract: Seventy-three patients with the features of 'cycloid psychosis', adopted from Perris and Leonhard, were identified from case records. Information concerning background, presenting illness and follow-up was compared with that from the case-records of patients with schizophrenic, affective and schizoaffective psychoses. The characteristic features of 'cycloid psychosis' were a female predominance and a remittent course. The 'cycloid' group resembled the conventional groups in some respects, but differences from schizophrenic, affective and, to a lesser extent, schizoaffective groups were also striking. The factors which might account for the apparent independence of the 'cycloid' group from other diagnostic categories are discussed.
mesh_terms: D000328:Adult; D001007:Anxiety / Q000175:diagnosis; D001714:Bipolar Disorder / Q000175:diagnosis / Q000628:therapy; D003863:Depression / Q000175:diagnosis; D005260:Female; D005500:Follow-Up Studies; D006778:Hospitals, Psychiatric; D006801:Humans; D008297:Male; D011596:Psychomotor Disorders / Q000175:diagnosis; D011618:Psychotic Disorders / Q000175:diagnosis*; D012008:Recurrence; D012559:Schizophrenia / Q000175:diagnosis