Impact of early environmental risk on associations between genetic liability to externalizing and trajectories of externalizing problems in early adolescence

Objective: We examined whether environmental risk (e.g., prenatal substance exposure, poverty, trauma, discrimination) moderates the association between genetic liability and developmental trajectories of externalizing problems (e.g., aggression, rule-breaking) during early adolescence. Method: The analytic sample (N=10,634) was drawn from the Adolescent Brain Cognitive Development (ABCD) Study. We used latent growth curve modeling to examine the development of externalizing problems from ages 9 to 14, based on longitudinal parent (Child Behavior Checklist [CBCL]) and youth-reported (Brief Problem Monitor [BPM]) measures. We evaluated associations with polygenic risk associated with externalizing (EXT PGS), exposure to environmental risk, and tested whether environmental risk moderated the relationship between EXT PGS and externalizing trajectories. Results: The EXT PGS was significantly associated with externalizing problems at baseline and with change in youth-report of externalizing problems over time. General environmental risk was significantly associated with both the intercept and slope factors. The association between the EXT PGS and the intercept (parent and youth-report) was significantly moderated by the general environmental risk factor. Also, the association between the EXT PGS and the development of externalizing behavior (parent-report slope) was significantly moderated by state-level risk factors. Conclusions: These results demonstrate that exposure to environmental risk amplified the association between genetic liability toward externalizing and externalizing behavior at age 9. In addition, state-level risk factors, which largely reflect the legality of medicinal and recreational cannabis where the youth reside, may amplify the association between the EXT PGS and the development of externalizing behavior.