1999). Genetic influences on adolescent substance use are also enhanced in environments with lower parental monitoring (Dick et al., 2007c) and in the presence of substance-using friends (Dick et al., 2007b). Similar effects have been demonstrated for more general externalizing behavior: genetic influences on antisocial behavior were higher in the presence of delinquent peers (Button et al., 2007) and in environments characterized by high parental negativity (Feinberg, Button, Neiderhiser, Reiss, & Hetherington, 2007), low parental warmth (Feinberg et al., 2007), and high paternal punitive discipline (Button, Lau, Maughan, & Eley, 2008).
