The incidence of mania in two areas in the United Kingdom.

The incidence of mania in an inner-city area was estimated by both a casenote search with later interview and a prospective interview method. The incidence was found to be twice as high as that in a more rural area, as estimated by the casenote-based method. Though a high proportion of the inner-city population were from ethnic minorities, particularly Afro-Caribbean, this could not explain the discrepancy. It is suggested that the incidence of mania is related to the mobility of the local population.