First-contact incidence rates of schizophrenia in Trinidad and one-year follow-up

Abstract

Background: Incidence rates of schizophrenia among UK African-Caribbeans have been reported as high. Various explanations including selective migration and genetic vulnerability have been proposed.

Method: In one calendar year, all new cases of psychosis presenting to various psychiatric services in two clearly defined geographical catchment areas in Trinidad-one in the rural south and the other an urban area-were studied. Standardised diagnostic instruments were applied and information collected using WHO screening and measurement instruments.

Results: A total of 56 cases were collected, giving an incidence rate of 2.2/1000 of broad schizophrenia with a rate of 1.6 for S+ schizophrenia.

Conclusion: These rates are similar to those from the WHO study in Honolulu and Aarhus, and much lower than the rates for African-Caribbeans in London. The cases were followed up for one year and the poor outcome rate for schizophrenia was 19%. The findings are discussed in a cross-cultural context and suggestions for future research made.