a single genetic factor, with no innovation over time, accounted for genetic influences on CAGE scores. Previous studies have indicated that alcohol consumption and problems are modestly to strongly genetically correlated in adulthood (Grant et al. 2009; Kendler et al. 2010; Dick et al. 2011); additional analyses would be necessary to determine whether the adolescent-limited or adult-onset genetic factors identified in the current study are more strongly related to alcohol problems. Previous research (described above) suggests that the latter is a more likely candidate. However, other studies have found little to no evidence of genetic influences on alcohol problems in adolescence (Rose et al. 2004; Knopik et al. 2009), raising the possibility that the genetic factors loading onto the CAGE score in late adolescence are atypical.
