religious involvement is more prevalent in African Americans than European Americans (Johnston et al., 1999; Kosmin and Keysar, 2009; Regnerus et al., 2003). The association between religiosity and reduced risk for problem drinking specifically among African Americans has been demonstrated as well (Stevens-Watkins et al., 2010), including in an earlier study based on the current sample (Heath et al., 1999). Furthermore, a high level of ethnic identification has been associated with greater disapproval of substance use, lower intentions to use drugs, lower rates of perceived peer use, and lower rates of alcohol use in African Americans (Chartier et al., 2009; Corneille et al., 2007; Pugh and Bry, 2007; Stock et al., 2012). In short, the differences between the AA and EA subsample twin models of problem use may reflect a protective effect of cultural norms against alcohol-related problems in African Americans, at least in early adulthood. The implication of these findings for European Americans is that, compared to African Americans, the environments to which they are exposed (e.g., peer, school, family) are contributing to a greater degree to problem drinking. Interventions aimed at altering environmental influences, for example, targeting parental attitudes toward alcohol use, or modifying perceptions of peer alcohol
