The incidence of first‐onset psychotic symptoms and paranoid ideation in a representative population sample followed from age 70–90 years. Relation to mortality and later development of dementia

Abstract

Background Limited data are available on the incidence of psychotic symptoms in the elderly. Objective To elucidate the incidence of first-onset psychotic symptoms in the elderly and their relation to mortality and later development of dementia. Method A population-sample (n = 392) born 1901–1902 was assessed from age 70–90 with psychiatric examinations, medical record reviews and from age 85, also with key-informant interviews. Individuals developing dementia were excluded. Result The cumulative incidence of first-onset psychotic symptoms was 4.8% (8.0% including key-informant reports in the total sample) and 19.8 % in those who survived to age 85. Sixty-four percent of those with first-onset hallucinations later developed dementia, compared to 30% of those with delusions and 25% of those without psychotic symptoms. Conclusions One fifth of non-demented elderly who survives up to age 85 develops first-onset psychotic symptoms. Hallucinations predict dementia, but most elderly individuals with first-onset psychotic symptoms do not develop dementia. Copyright © 2006 John Wiley & Sons, Ltd.