A controlled family study of late-onset non-affective psychosis (late paraphrenia).
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.
Howard
R J
RJ
Institute of Psychiatry, London.
Graham
C
C
Sham
P
P
Dennehey
J
J
Castle
D J
DJ
Levy
R
R
Murray
R
R
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