Are there genetic influences on addiction: evidence from family, adoption and twin studies

Aims In this exciting era of gene discovery, we review evidence from family, adoption and twin studies that examine the genetic basis for addiction. With a focus on the classical twin design that utilizes data on monozygotic and dizygotic twins, we discuss support in favor of heritable influences on alcohol, nicotine, cannabis and other illicit drug dependence. Methods We review whether these genetic factors also influence earlier stages (e.g....