Genetic strategies in biological psychiatry.

Studies of the etiology of schizophrenia and other psychiatric illnesses may be executed by using a genetic framework in the experimental design. This article describes research strategies for identifying the genetic factors that produce a vulnerability to a psychiatric illness. The proposed strategies evaluate the role of a given genetic factor by comparing the transmission of this factor within pedigrees to the transmission of that illness. In a biologically heterogeneous disorder, these strategies can be used to identify homogeneous subgroups. This report also describes a strategy for identification of the environmental events that promote the development of a psychiatric illness, either independently or in conjunction with the genetic diathesis.