Illicit Psychoactive Substance Use, Heavy Use, Abuse, and Dependence in a U.S. Population-Based Sample of Male Twins

Illicit psychoactive substance use, abuse, and dependence are major public health problems. To develop informed approaches to prevention and treatment, we need to understand the sources of individual differences in risk. Substantial evidence suggests that the liability to psychoactive substance use disorder (PSUD) aggregates in families.1-6 Both twin7-10 and adoption11-13 studies suggest that part of this familial aggregation is due to genetic factors.