Generalizability of the present research is limited because SAAF–T was designed to meet a need in rural Southern communities for efficacious prevention programming for African American adolescents. The findings’ applicability with ethnically and socioeconomically diverse participants residing in urban and rural locations must be established empirically. Even though the distribution of DRD4 exon III VNTR alleles has been shown not to vary between persons of African and European descent (Chang, Kidd, Livak, Pakstis, & Kidd, 1996; Chen, Burton, Greenberger, & Dmitrieva, 1999), in attempting future replications, researchers should note whether their study populations differ in the distribution of these alleles. Such studies are important to an understanding of the etiology of substance use and abuse. These issues aside, the present study demonstrates the utility of using randomized prevention trials to test G×E hypotheses and furthers understanding of substance use etiology.
