Controversies and Consistencies in Psychiatric Genetics

The methodology in psychiatric genetics, including family studies, twin studies, and adoption strategies, developed during the last 70 years to a high degree of perfection, has established beyond doubt the heritability of the major psychoses, the schizophrenic and manic-depressive disorders. In spite of recent refinements, including twin-family-study strategies, dual mating strategies, and advanced mathematical models and statistics the mode of inheritance is still undetermined. Evidence for heterogeneity in both schizophrenia and manic-depressive psychosis has been brought up leading to new approaches in diagnostic delimitations. However, the final solution of this issue probably has to await the finding of a genetic marker, for which recent advances in molecular biology as seen in Huntington's disease may give some hope.