Incidence of bipolar affective disorder in three UK cities: results from the AESOP study.

Background: There has been a relative dearth of epidemiological research into bipolar affective disorder. Furthermore, incidence studies of bipolar disorder have been predominantly retrospective and most only included hospital admission cases.
Aims: To determine the incidence of operationally defined bipolar disorder in three areas of the UK and to investigate any differences in gender and ethnicity.
Method: All patients who contacted mental health services with first-episode psychosis or non-psychotic mania between September 1997 and August 1999 were identified and diagnosed according to ICD-10 criteria. Incidence rates of bipolar affective disorder were standardised for age and stratified by gender and ethnic group across the three areas.
Results: The incidence rate per 100,000 per year in south-east London was over twice that in Nottingham and Bristol. There was no significant difference in the rates of disorder in men and women. Incidence rates of bipolar disorder in the combined Black and minority ethnic groups in all three areas were significantly higher than those of the comparison White groups.
Conclusions: The incidence of bipolar disorder was higher in south-east London than in the other two areas, and was higher among Black and minority ethnic groups than in the White population.