Cannabis use in college: Genetic predispositions, peers, and activity participation

Among adult college students in the US, cannabis use is common and associated with considerable negative consequences to health, cognition, and academic functioning, underscoring the importance of identifying risk and protective factors. Cannabis use is influenced by genetic factors, but genetic risk is not determinative. Accordingly, it is critical to identify environments that reduce risk among those who are at elevated genetic risk. This study examined the impact of polygenic scores for cannabis initiation, various forms of social activity participation, and peer deviance on recent cannabis use. Our aim was to test whether these environments moderate genetic risk for cannabis use.

Data came from a longitudinal sample of undergraduate college students of European American (EA; N_EA = 750) and African American (AA; N_AA = 405) ancestry. Generalized estimating equations with a logit link function were used to examine main effects and two-way interactions.

Engagement with church activities was associated with lower probability of cannabis use. Peer deviance was associated with higher probability of cannabis use. Engagement with community activities moderated the influence of the polygenic risk score in the EA sample, such that PRS was associated with recent cannabis use among those who never engaged in community activities. This effect did not replicate in AAs, which may have been due to the portability of PRS based on EA discovery samples.

Results suggest that community activities may limit the influence of genetic risk, as associations between PRS and cannabis use were only observed among individuals who never engaged in community activities.