The differential impact of SAAF was not attributable to different ending points for intervention-targeted parenting as a function of youth genotype at DRD4. Rather, the SAAF program was designed to equalize the parenting environments for youth with differing genotypes. Caregivers showed equivalent changes in response to intervention regardless of youth genotype at DRD4 and showed significantly greater changes in SAAF than in the control condition. Accordingly, the effects support a susceptibility hypotheses and not simply a genetic risk explanation for the impact of the 7-repeat allele of DRD4. This finding has the potential to change understanding of the nature of vulnerability to early substance use and strengthens the argument for provision of preventive programming focused on substance use outcomes.
