Genetic risks in schizophrenia: Cross-national prospective longitudinal high-risk studies

Prospective longitudinal studies are a powerful means to identify the causal chains of biological and environmental factors that underlie the development of serious mental disorders. Schizophrenia is one of these disorders. Schizophrenia is a multifactorial neurodevelopmental disorder whose specific molecular genetic, epigenetic, stochastic, and environmental bases remain elusive. The chronic debilitating nature of the disorder places a heavy emotional and financial burden on the individual, family, and society. Although the lifetime prevalence of schizophrenia is 1% in the general population that has passed through the risk period, it accounts for up to 3% of total national health-care expenditures in Western countries (). The hypothetical ability to intervene in the developmental progression of the disorder at a point before breakdown is contingent upon the elucidation of early behavioral and other markers of genetic liability to the disorder and their triggers. In this chapter, we focus on research aimed at early detection of markers that may predict to the later onset of schizophrenia. Once these markers are identified, intervention can, at least in principle, be targeted to those individuals most at risk for the disorder.