There are several notable strengths of this study. All previous studies that have examined genetic moderation of intervention effects on adolescent alcohol use only examined differences in the levels of use at a particular age or follow-up (typically 2–3 years later) in homogenous ethnic groups and mostly focused on early to mid-adolescence (between 11–15 years old), when the prevalence is generally low. This study investigated developmental trajectories in a group of ethnically diverse children followed longitudinally from grade 7 to 2 years post-high school. This design provided the opportunity to examine individual differences in the rates of growth, which have been shown to be particularly predictive of later outcomes (Duncan et al. 1997; Mason et al. 2010). A few limitations of this study warrant attention and should be addressed in future studies. First, the sample size in the genetic analyses was nevertheless small, especially as fitted to a complex model like a latent growth curve model. Replication with a larger sample size is needed for more robust conclusions. However, the experimental nature of this RCT of the Fast Track project
