title: A controlled family study of late-onset non-affective psychosis (late paraphrenia).
abstract: BACKGROUND
  The relationship between those schizophrenia-like conditions that have their onset in late life and early-onset schizophrenia is unclear. Very few family history studies of patients with late-onset psychosis have been reported, and it is not known whether their relatives have an increased risk of psychosis.
  
  
  METHODS
  Information was collected on the psychiatric morbidity of 269 first-degree relatives of patients with schizophrenia or delusional disorder with an onset after the age of 60 (late paraphrenia), and 272 first-degree relatives of healthy elderly control subjects, using a research diagnostic instrument.
  
  
  RESULTS
  With a narrow age range (15-50 years) at risk, the estimated lifetime risk of schizophrenia was 1.3% in the relatives of both cases and controls. With a wider age range (15-90 years) at risk, estimated lifetime risk of schizophrenia was 2.3% for the relatives of cases and 2.2% for the relatives of controls. However, depression was significantly more common among the relatives of cases than controls.
  
  
  CONCLUSIONS
  Those schizophrenia-like psychoses with onset in late life are not genetically associated with schizophrenia.
authors.affiliation: Institute of Psychiatry, London.
authors.forename: R J
authors.initials: RJ
authors.lastname: Howard
authors.forename: C
authors.initials: C
authors.lastname: Graham
authors.forename: P
authors.initials: P
authors.lastname: Sham
authors.forename: J
authors.initials: J
authors.lastname: Dennehey
authors.forename: D J
authors.initials: DJ
authors.lastname: Castle
authors.forename: R
authors.initials: R
authors.lastname: Levy
authors.forename: R
authors.initials: R
authors.lastname: Murray
mesh_terms: D000328:Adult; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D003702:Delusions / Q000209:etiology; D005192:Family Health; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D011618:Psychotic Disorders / Q000209:etiology*; D012559:Schizophrenia / Q000209:etiology