et al. (2007), using the classic univariate moderation model, showed that genetic influences on adolescent substance use were greater at lower levels of parental monitoring. In addition, Miles et al. (2005) found a moderating effect of parental characteristics on adolescent female alcohol use. They showed that at higher levels of parental closeness the genetic influences on adolescent alcohol use are lower. In all of these instances, genetic influences on alcohol use increased in the context of environments characterized by high levels of social opportunity to use and/or lack of social control (e.g., higher peer deviance, lower parental monitoring) (Dick & Kendler, 2012; Shanahan & Hofer, 2005). The literature on stressful life events is more nuanced. Hicks et al. (2009), using a bivariate model, demonstrated that stressful life events moderated the genetic effect on externalizing disorders (including alcohol dependence) in adolescents. Again, genetic influences were greater in the context of more stressful life events. However, Button et al. (2007) found a positive genetic correlation between negative life events and externalizing behavior, but no GxE interaction.
