The Genetics of Schizophrenia: A Review

Abstract

Family, twin, and adoption studies have produced strong evidence that genes play a major role in schizophrenic conditions. These conventional approaches, however, are not able to reveal anything about the way in which genes influence that disease except that the family prevalence of schizophrenia is too low to fit a classical Mendelian transmission mode. New molecular biological techniques offer bright possibilities for identifying the chromosomal loci of genetic diseases, but these techniques rely for their effectiveness on a Mendelian distribution of the trait under investigation. We show how psychological methods can play a decisive role in making these new biological techniques available for the study of schizophrenia by expanding the phenotype (schizophrenia) to include associated behaviors that fit a model of transmission by major loci.