Genes, Roommates, and Residence Halls: A Multidimensional Study of the Role of Peer Drinking on College Students’ Alcohol Use

Abstract

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' selfreport. 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 (b = 0.12), perceptions of peer drinking (b = 0.37), and roommates' self-reported drinking (b = 0.10) predicted alcohol use (all ps < 0.001), while average alcohol use across residence hall did not (b = À0.01, 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.

Integrating a Quasi‐experimental Design to Study Gene‐by‐Environment Interaction on Alcohol Use

“…Both residence defined based on fraternity/sorority housing and perceived peer drinking at the residence level have been associated with drinking behaviors (Larimer et al., ). Different from the findings of these studies, Smith and colleagues () did not find an association between residence hall drinking and college student alcohol use. The authors noted that this may be due to insufficient statistical power or limited interactions between students who lived on multiple floors, which are both plausible explanations.…”

“…Smith and colleagues () have extended these prior studies in 3 important ways. First, the measurement of peer drinking was not solely based on college students’ perception.…”

“…Although longitudinal research in this area has helped clarify the direction of effects over time (e.g., Simons‐Morton and Chen, ), inferences about the causal associations are often still limited due to the use of observational and self‐report data. The work of Smith and colleagues () in Volume 43, Issue 6 of Alcoholism: Clinical and Experimental Research offers novel insights into how these issues could be resolved within the context of studying peer and genetic factors as contributors to alcohol use among college students.…”

“…Using a genetically informed sample of 755 college students who lived in residence halls, Smith and colleagues () capitalized on random assignment of roommates as a natural experiment to examine the effects of alcohol use by roommates on college student drinking. The use of roommate assignment as a natural experiment can be found in other areas of study such as in education (Zimmerman, ).…”

“…Second, Smith and colleagues () took into account average drinking at the residence hall level using multilevel modeling. Understanding college student drinking behaviors within the context of where they lived is an important consideration.…”