Adolescents’ age and sex were included as covariates for adolescent externalizing behaviors, parental knowledge, and peer substance use at both time points. We used the MODEL INDIRECT command in Mplus to examine indirect effects of externalizing PGS on T2 externalizing behaviors via T1 parental knowledge and T1 peer substance use. This provides a test of specific indirect effects in addition to the total indirect and direct effects of externalizing PGS on adolescent externalizing behaviors. Since multiple indirect pathways were examined simultaneously, specific indirect effects reflect each of the specific pathways (e.g., EXT PGS→T1 parental knowledge →T2 externalizing behaviors) while also accounting for the shared associations between them. We evaluated indirect effects using bias-corrected bootstrapped (1000 times) 95% confidence intervals. Confidence intervals not including zero would provide evidence of statistically significant indirect effects.
