Investigating Putative Genetic and Environmental Forms of Schizophrenia: methods and findings

Abstract

The existence of separate genetic and environmental forms of schizophrenia has been proposed as the basis for the probable heterogeneity in the etiology of schizophrenia. The rationale for a familial/sporadic strategy that compares positive versus negative family history cases and concordant versus discordant MZ twin pairs is discussed. A review of empirical findings from research utilizing the familial/sporadic strategy is presented. A number of methodological problems that have implications for the application of the strategy and the interpretation of results, such as misclassification, are discussed. It is concluded that the clustering of positive findings in certain domains suggests that this approach holds some promise for elucidating the role of genetic and environmental factors in schizophrenia.