Incidence of schizophrenia in an urban community in madras

The incidence rate of an illness is a vital epidemiological measure for investigating etiology. Incidence estimates of schizophrenia from different parts of the world have shown variations, due to differences in the diagnostic criteria, measurement techniques and operational definitions used. In contrast to the prevalence studies in India, incidence surveys haw been sparse and the rates obtained relatively higher as compared to the west. As part of an ICMR Longitudinal Study of Functional Psychoses in an urban community in Madras, the incidence of schizophrenia was estimated in the slums. The case finding methods included a door to door survey and a leakage study. Cases defined using standardized diagnostic criteria, were identified using IPSS and PSE. The incidence rate was 0.21/1,000 by the community survey and 0.41/1,000 by the leakage study. This paper describes the study and discusses its relevance in India.