2 - Geographical variation in incidence, course and outcome of schizophrenia: a comparison of developing and developed countries

Summary

Schizophrenia was not identified as a discrete illness until the dawn of the 20th century and was once widely considered a ‘disease of civilization’. Later evidence suggested that at least some cases of schizophrenia could be identified in any community at whatever level of development, but the incidence rate of schizophrenia in developing countries is still largely a matter for bold speculation based on minimal data. In the meantime, strong evidence has emerged for a surprising result: the course of schizophrenia is more benign in the developing countries, where treatment options are minimal.

In this chapter, we review the evidence for differences in incidence as well as course of schizophrenia between developing and developed countries. Present day researchers often prefer the more neutral designation of ‘low-income’ versus ‘highincome’ countries, which does not imply any universal continuum of economic development. For clarity, however, we retain the term used in the literature we review.

Incidence

In a recent review of schizophrenia incidence studies, the annual incidence rates ranged from 0.04 to 0.58 per 1000 (Eaton, 1999). Because the observed variation is likely to result in part from differences in the methods of individual studies (Bresnahan et al., 2000), its meaning with respect to geographic distribution is unclear. Systematic patterns of variation are obscured by these and other artifacts.

Here we have chosen to examine variation across sociocultural settings by comparing developing and developed countries.