Genetic influences in human substance abuse.

The importance of clinical studies to genetic research on substance abuse is discussed. This paper compares the advantages and limitations of methods employed in clinical studies to those employed in animal studies. It stresses the complementary nature of human and animal studies for improving our understanding of genetic influences in substance abuse. Finally, it reviews findings from adoption and twin studies of substance abuse. Whereas much is known about genetic influences in human alcoholism, relatively little is known about genetic influences in other types of drug abuse. This disparity is directly related to the amount of research that has been conducted in the two areas over the past several years.