Incidence and distribution of first-episode mania by age: results from a 35-year study.

Abstract

BACKGROUND: Few epidemiological studies have investigated incidence by age or age at onset distributions for mania or bipolar disorder. The current study aimed to determine these in a defined area in south-east London, over a 35-year period. METHOD: All cases of first-episode mania presenting to psychiatric services in Camberwell, south-east London, between 1965 and 1999 were identified. Incidence rates by age, using 5-year age-at-onset bands, were estimated and the structure of the age-at-onset distribution for first-episode mania was investigated using finite mixture distributions (admixture analysis). RESULTS: The incidence of DSM-IV bipolar I disorder (BP I), first manic episode peaked i..