Sixth, we examined peer substance use and parental knowledge as two plausible pathways underlying the mechanisms through which genetic risks influence externalizing in adolescence. This study offers an illustration of broad strokes of patterns representing the interplay between polygenic risk, parenting, peers, and adolescent externalizing behavior, but these broad patterns require closer examination in future studies, both to replicate these findings and consider other explanatory pathways and shared processes from multiple levels and contexts that may underpin the genetic influences on adolescent behavior and outcomes. Finally, our study focused on adolescence, and by T1 in this study, the constructs examined were already showing strong interconnections. This suggests that many of the gene-environment correlation processes began earlier in development. Future research should consider earlier antecedents and rGE processes at younger ages to further delineate how genetic risk unfolds across development and interfaces with the environment.
