To present an overview of the status of genetics of mental disorders and to describe the role of genetic epidemiology in the future of the implementation of the human genome initiative. Reviews evidence on familial recurrence risk for major mental disorders and approaches to identify genes for complex disorders. The next decade will witness shifts in approaches of both epidemiology and genetics to address sources of complexity of the mental disorders. Descriptive genetic epidemiology will evolve into analytic genetic epidemiology by shifting the key questions from estimation of the magnitude of mental disorders to identification of risk and protective environmental factors that may be informative for both etiology and prevention. Genetics research will expand to population-based studies for complex disorders and will employ designs and methods that incorporate sources of complexity. In summary, the next era of human genetics will witness major shifts in approaches to identify the genes underlying mental disorders. The contributions of genetic epidemiology to translate advances in molecular genetics to public health are discussed.