Ageing and affective disorders: the age at first onset of affective disorders in Scotland, 1969-1978.

First admission rates from 1969-78 for Scottish psychiatric units were calculated for discharge diagnoses of affective psychosis for each five-year age-group from 15 years to over 74 years. There were clear-cut linear increases in rates of depressive psychoses, mania, and all affective psychoses, consistent with a relatively steady increase in the rate of first-onset affective psychoses with increasing age. These findings are discussed in terms of social, psychological, and biological hypotheses of the causes of affective disorder. It is argued that no single factor could produce the observed linear increases with age and that the data appear more consistent with an integrative aetiological model of affective disorder.