Other studies suggest that social environments that encourage drinking may diminish the protective genetic effects of alcohol metabolizing variants (Hasin et al., 2002; Higuchi et al., 1994; Irons et al., 2007; Irons et al., 2012). However, to our knowledge, no study has explored the interplay of the ADH1B rs1229984 variant and the important social context of peer drinking during the critical developmental period of adolescence when alcohol use is initiated and drinking patterns are established. Peer drinking has long been recognized as a strong risk factor for adolescent drinking problems (Curran et al., 1997; Reifman et al., 1998), and recently, twin studies have provided evidence that peer drinking modifies heritable variation in adolescent alcohol involvement (Agrawal et al., 2010; Dick et al., 2007; Guo et al., 2009; Harden et al., 2008).
