A long tradition in psychiatry has focused on parental traits that
directly influence the liability to psychiatric disorders in offspring.
Because these traits rarely resemble the disorders they cause, traditional
models of cultural transmission (which assume that "like perpetuates like")
may not be appropriate. The author develops and illustrates several models
for indirect vertical cultural transmission of psychiatric illness. These
models generate falsifiable predictions about the pattern of risk in
relatives of affected individuals. For example, all such models predict a
substantially higher risk of illness in siblings than in offspring of
affected individuals. It is now possible to develop and test rigorous
models for the cultural transmission of psychiatric illness.