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Background: The period of college represents a particularly risky developmental stage with regard to alcohol use, as college students engage in more risky drinking behaviors than their noncollege peers, and such problematic alcohol use is associated with far‐reaching negative consequences. Existing findings from genome‐wide association studies (GWAS) indicate that alcohol consumption has a complex polygenic etiology. Currently, there is a lack of studies examining genetic risk for alcohol consumption using polygenic risk scores (PRS) in college samples. In this study, we examined whether alcohol‐specific and risky behavior–related PRS were longitudinally associated with alcohol consumption among college students and whether this effect might be partially mediated by impulsivity domains. Methods: The sample included n = 2,385 European ancestry (EA) and n = 1,153 African ancestry (AA) college students assessed over the course of 4 years. To indicate genetic risk, 2 PRS were created based on recent large‐scale GWAS: alcohol consumption (Liu et al., 2019) —drinks per week (DPW)‐PRS and risky behaviors (Linnér et al., 2019) —RISK‐PRS. The main outcome was alcohol consumption, measured across 4 waves of follow‐up data. The UPPS‐P impulsivity subscales were examined as mediators of the genetic effect on alcohol consumption. Results: The results from structural equation modeling showed that among EA students, both DPW‐PRS and RISK‐PRS had significant positive effects on alcohol consumption above and beyond UPPS dimensions and control variables. RISK‐PRS explained larger portion of variance in alcohol consumption than DPW‐PRS. RISK‐PRS showed a significant indirect effect on alcohol consumption through sensation seeking and lack of perseverance; no significant indirect effect of DPW‐PRS was found. No significant association of either PRS or alcohol consumption was found for AA participants. Conclusions: The current results found that PRS related to more broadly defined risky behaviors predicted alcohol consumption across college years and that this association was partially mediated via dimensions of impulsivity. [ABSTRACT FROM AUTHOR]

Background: Peer drinking is one of the most robust predictors of college students' alcohol use and can moderate students' genetic risk for alcohol use. Peer effect research generally suffers from 2 problems: selection into peer groups and relying more on perceptions of peer alcohol use than peers' self‐report. The goal of the present study was to overcome those limitations by capitalizing on a genetically informed sample of randomly assigned college roommates to examine multiple dimensions of peer influence and the interplay between peer effects and genetic predisposition on alcohol use, in the form of polygenic scores. Methods: We used a subsample (n = 755) of participants from a university‐wide, longitudinal study at a large, diverse, urban university. Participants reported their own alcohol use during fall and spring and their perceptions of college peers' alcohol use in spring. We matched individuals into their rooms and residence halls to create a composite score of peer‐reported alcohol use for each of those levels. We examined multiple dimensions of peer influence and whether peer influence moderated genetic predisposition to predict college students' alcohol use using multilevel models to account for clustering at the room and residence hall level. Results: We found that polygenic scores (β = 0.12), perceptions of peer drinking (β = 0.37), and roommates' self‐reported drinking (β = 0.10) predicted alcohol use (all ps < 0.001), while average alcohol use across residence hall did not (β = −0.01, p = 0.86). We found no evidence for interactions between peer influence and genome‐wide polygenic scores for alcohol use. Conclusions: Our findings underscore the importance of genetic predisposition on individual alcohol use and support the potentially causal nature of the association between peer influence and alcohol use. [ABSTRACT FROM AUTHOR]