Schizophrenia, social class and immigrant status: the epidemiological evidence

Background - By the mid-1960s, the importance of socio-economic status for schizophrenia had been demonstrated in terms of differences between social-class groups in prevalence and incidence rates, illness course and outcome, and treatment experience. In the causation - selection debate, however, opinion had swung in favour of the selection hypothesis. Aims To reassess evidence on the social-class distribution of schizophrenia in Britain, and to compare this body of research with population-based studies of schizophrenia risk in socially disadvantaged ethnic minorities. Method - Systematic review of medical and psychological data-bases. Results - Epidemiological research, while confirming the importance of premorbid social decline, has also provided support for the environmental 'breeder' hypothesis. High psychosis rates have been confirmed in ethnic minorities; in particular among Afro-Caribbean and other Black immigrants whose low social status cannot be accounted for by selective downward social drift or segregation. Conclusions - There are striking parallels, both in the epidemiology of schizophrenia and in social characteristics, between the lower-class indigenous groups highlighted by earlier psychiatric surveys and African-Caribbean populations in Britain's inner cities today. These similarities underline the need for a broader perspective in the search for environmental risk factors.