The association between the OPRM1 gene and deviant peer affiliation is especially noteworthy in light of mounting evidence from animal models and more recently from human data that the A118G SNP of the OPRM1 gene modulates individual differences in the capacity to experience social reward and the need for affiliation, with carriers of the G allele demonstrating greater tendencies to engage in and experience reward from social situations (Troisi et al., 2011a). At the same time, research also shows that individuals carrying the G allele experience heightened sensitivity to social rejection on self-report measures as well as increased neuronal activity in response to social rejection across multiple brain regions that govern the processing of physical pain (Troisi et al., 2011b; Way et al., 2009). Although this work was done with adult samples and requires further study among adolescents, the possible implications of these findings for the present study are intriguing. Adolescent carriers of the G allele may be prone to affiliating with deviant peers in part due to their heightened sensitivities to social reward and to fear of social rejection.
