The means, standard deviations, and zero order correlations among the study variables are presented in Table 1. Using independent t-tests, there were no mean differences between carriers of the s allele and ll allele homozygotes on any of the study variables at the baseline assessment. As expected, participation in SAAF was associated with changes in early substance use and OXTR methylation was associated with early substance use for carriers of the 5-HTTLPR “s” allele, but were not significantly correlated for ll carriers (simple correlations within genotypes provided in the supplemental materials table S2). There was no significant correlation of “Percent European Ancestry” with substance use initiation.
