title: Heterogeneity of cycloid psychoses: a latent class analysis.
abstract: BACKGROUND
  Three hypotheses have been proposed in regard to the origin of cycloid psychoses: (1) they are an independent nosological entity; (2) they are atypical cases of affective disorders; and (3) they are a heterogeneous group of disorders. This study examined the heterogeneity hypothesis by attempting to delineate distinct affective and non-affective subgroups.
  
  
  METHODS
  In 60 cases drawn from a classic study of cycloid psychoses by Perris (1974), latent class analysis was used to delineate subgroups.
  
  
  RESULTS
  Two classes were identified in the analysis: one characterized by the convergence of affective symptoms and family history of affective disorders and the other by the relative paucity of such features.
  
  
  CONCLUSIONS
  Cycloid psychoses are composed of at least two subgroups, distinguishable on the basis of symptoms and family history.
authors.affiliation: Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
authors.forename: R
authors.initials: R
authors.lastname: Mojtabai
mesh_terms: D000208:Acute Disease; D000328:Adult; D000341:Affective Disorders, Psychotic / Q000145:classification / Q000235:genetics / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D010375:Pedigree; D010507:Periodicity