The observation that the ADH1B variant is associated with a decreased risk of first intoxication and first DSM-5 symptom during adolescence (Table 2) extends previous findings that this variant protects against alcohol-related health problems in adulthood (Bierut et al., 2012; Gelernter et al., 2014; Li et al., 2011). Despite having an early role in the trajectory of drinking behaviors, the ADH1B variant was not associated with drinking initiation, consistent with the hypothesized mechanism of action that requires alcohol exposure (Edenberg and Foroud, 2013; Hurley and Edenberg, 2012). This specific example of a genetic variant that influences early drinking milestones, but not initiation, builds on twin and adoption study findings that genetic factors contribute to the development of adolescent alcohol-related problems, and environmental factors more strongly drive drinking initiation (Hopfer et al., 2003; Lynskey et al., 2010).
