Second, alcohol use and antisocial behavior may share common causes. As discussed previously, antisocial behavior and alcohol use are part of a broader externalizing behavior factor (Krueger et al., 1998, 2002). It is also known that common genetic influences contribute to a spectrum of correlated externalizing behaviors (Dick et al., 2005, 2008, 2009; Kendler et al., 2003; Krueger et al., 2002; Slutske et al., 1998), and that genetic associations with these behaviors may change across development. For example, variants in the GABRA2 gene are associated with conduct disorder during childhood, and then alcohol problems beginning in late adolescence through adulthood (Dick et al., 2006, 2013). This suggests that genetic predispositions may manifest differently at different ages, which may be due to environmental changes such as greater autonomy and greater opportunities to express those predispositions. This may explain the sequential expression of antisocial behavior and alcohol use and could provide an alternative explanation for the directional relationships between the 2 behaviors found here. As the field continues to identify genes associated with alcohol problems and antisocial behavior, future models that incorporate
