Genetic Epidemiology in Psychiatry

THIS ISSUE of theArchivescontains three articles that examine diverse aspects of the genetic epidemiology of psychiatric illness.1-3These articles attest to the vibrancy of this field, which represents a hybrid discipline, combining features of traditional medical genetics and epidemiology. While medical genetics has generally focused on classic, rare, Mendelian disorders where the genetic signal is so powerful that environmental effects are irrelevant, genetic epidemiology examines common, familial disorders where an inherited vulnerability interacts with environmental risk factors in often complex and uncertain ways.4,5 As demonstrated by these articles, the field of the genetic epidemiology of psychiatric illness has been maturing rapidly. As little as a decade ago, most publications focused solely on the assessment of the familial or genetic transmission of psychiatric disorders. Although these questions are fundamental, they represent only the beginning rather than the conclusion of the endeavor. Each article examines a critical issue