although this study was limited by a relatively small sample size and focused on only a single polymorphism in DRD4. Investigations with respect to PRS in the context of GxE have recently emerged as well, as high PRS for alcohol problems was recently shown to be more robust in predicting alcohol problems in an adolescent twin sample (i.e., Finnish Twin Study) under conditions of high peer deviance and low parental knowledge (Salvatore et al., 2014a), although the magnitude of these interactive effects were small (~.30% of the variance in alcohol problems). Collectively, the evidence suggests that genetic risk may be moderated by peer influences in predicting more broadly defined alcohol-related phenotypes in adolescents.
