Long-term outcome of late-onset schizophrenia: 5-year follow-up study.

BACKGROUND There is controversy about whether late-onset schizophrenia is a precursor of cognitive decline. AIMS To examine the long-term outcome of a group of patients with late-onset schizophrenia. METHOD Patients with onset of DSM-III-R schizophrenia at age 50 years or over, but without dementia, and a healthy control group were assessed at baseline (n=27 and n=34, respectively), after 1 year and after 5 years (n=19 and n=24, respectively) on measures of psychopathology, cognition and general functioning, and compared on rates of decline and incidence of dementia. RESULTS Nine patients with late-onset schizophrenia and none of the control group were found to have dementia (5 Alzheimer type, 1 vascular, 3 dementia of unknown type) at 5-year follow-up. There appeared to be a subgroup of late-onset schizophrenia patients without signs of dementia at baseline or at 1 year follow-up who subsequently declined. CONCLUSIONS Late-onset schizophrenia may be a prodrome of Alzheimer-type dementia. More longitudinal studies are required to determine its nosological status.