Increasing age is a risk factor for psychosis in the elderly.

We examined the association between ageing and the administrative incidence rate of late onset (after age 59) non-organic, non-affective psychosis in two samples of patients aged 60 years or older who were first admitted to hospital in (1) The Netherlands between 1978 and 1992 (n = 8010) and (2) nine regional health authorities in England and Wales (n = 1777) between 1976 and 1978. There was a linear trend in the association between increasing age and first admission rates for non-organic, non-affective psychosis in the elderly, after adjustment for the possible confounding effects of time trend and gender, corresponding to an 11% increase in the incidence with each 5-year increase in age. These observations support a connection between degenerative brain processes and onset of non-affective psychosis in the elderly.