In this issue of the Journal,1 Blum and colleagues report a surprisingly strong association between an allele of the dopamine D2 receptor and alcoholism. This observation is provocative and promising but must be regarded with caution. Here is the background.
Research during the last two decades has provided strong evidence that at least part of the vulnerability to becoming alcoholic on exposure to alcohol is inherited.2 In most twin studies, identical (monozygotic) twins have been found to be approximately twice as likely to be in concordance for alcoholism as fraternal (dizygotic) twins of the same sex. The strongest evidence for a genetic role in alcoholism comes from the adoption studies of Bohman, Cloninger, and others.2 Young children who were adopted away from alcoholic biological parents and raised in a nonalcoholic family developed many more alcohol problems as adults than similar adoptees whose biological parents were not