Psychiatric genetics and the primary prevention of psychiatric disorders.

The role of genetic factors in the etiology of psychiatric disorders is one that has been long debated. Three 'families' of psychiatric disorders--which 'run' in families--have been observed: the schizophrenias, the affective disorders, and the St. Louis 'family of disorders' which includes antisocial personality, alcoholism, Briquet's syndrome and the hyperactive child syndrome. Such familial clustering could obviously occur on the basis of genetic transmission or on the basis of social learning within the family. Beginning in the 1960's, a number of adoption studies have been conducted. These studies permit an assessment of the relative contributions of genetic and environmental factors to the disorders mentioned above. This paper briefly reviews the strategy of these studies and the results they have obtained. An awareness of these studies and their results is essential to those concerned with the primary prevention of psychiatric disorders.