Association Between the D2 Dopamine Receptor Gene and Alcoholism

The idea that alcoholism is familial has been accepted for centuries. However,familialdoes not translate directly tohereditary. Studies on twins, raised together and apart (adoption studies), clearly show that there is a major genetic component to alcoholism. In fact, more recent studies on a total of 1775 children born to single mothers in Stockholm, Sweden, between 1930 and 1949, their adoptive families, and their biological parents have identified at least two of the following classes of alcoholics: milieu-limited (type 1) and malelimited (type 2). Although type 2 alcoholism is more frequent in men, their female siblings show an abnormally high prevalence of somatization disorder. Type 2 alcoholism is highly inheritable from father to son, regardless of environmental background. On the other hand, in the Swedish adoption study, the risk of type 1 alcoholism to siblings increased as a function of both biological family history and adoptive en- See