In contrast to this clear result, analyses addressing the possible role of OXTR variation on the link between exposure to substance using peers and adolescents’ own alcohol use and how this association might vary across intervention conditions provided more mixed results. Although the three-way interaction among the OXTR score, peer substance use, and intervention status was significant, like all adolescents affiliating with low substance-using peers, the alcohol use levels of the high OXTR risk adolescents who affiliate with low substance-using peers in the intervention, whose use drove this result, were low compared to the full sample. Rather than finding that OXTR substantially moderated the impact of peers, or the combined impact of peers and intervention, affiliations with substance-using peers were consistently linked to individuals’ own alcohol use across all combinations of OXTR variation and intervention conditions.
