Finally, it is important to note that, in the current study, we found effects of the SAAF intervention on escalation of risk behavior whereas in prior work we have focused primarily on its initiation (e.g. Brody, Murry, Gerrard et al., 2006; Brody, Beach, Philibert, Chen, & Murry, 2009). The emergence of different genetic moderators for initiation (e.g. 5HTT) than for escalation (e.g. DRD4) of risk behavior across adolescence may inform developmental models of youth substance use. In particular, the distinct phases of substance use initiation, substance use escalation, and substance use maintenance into young adulthood may constitute separable processes with differing genetic substrates.
