deviant peer affiliation were associated with a low prevalence of AUDs regardless of genotype. These data build on recent findings from longitudinal twin studies that indicate that genetic influences on adolescent substance use are strongest when parental monitoring is relatively low and when teenagers have a larger number of deviant peers (Dick et al., 2007; Guo et al., 2009). On the whole, these findings add to a growing body of evidence, now observed in both quantitative and molecular genetic research, which shows that well-supervised and non-permissive family environments can restrict manifestation of genetic predispositions for alcoholism while affiliation with deviant peers can potentiate this risk. Our findings provide further support for intervention strategies designed to decrease teenage alcohol use by increasing affiliation with non-deviant peers. Such interventions may in effect delay the development of heavy use and problems, and this may be effective across levels of alcoholism diathesis.
