demonstrate an association between this SNP and the YSR externalizing score (Dick, Aliev, Latendresse, Hickman, et al., 2013). This potential relationship between disruptive behavior and rs279871 builds upon our previous work demonstrating significance for both the number of CD symptoms and the YSR externalizing score as predictors for the age of drinking initiation (Kuperman et al., 2013) and provides further support for using rs279871 to determine whether it improves our previous model.