Lastly, there was an imperfect correspondence between our sample and the discovery sample used to create polygenic scores. The discovery sample consisted of older individuals from a population-based sample (Schumann et al., 2016), while the target sample in the present study consisted of a group of young adults enriched for risk. Moreover, our study only included participants of European ancestry; therefore, it is possible that our findings may not extend to individuals of other ancestral backgrounds. Future research should address these limitations by utilizing a better matched and more ethnically diverse discovery sample, although we note that most large-scale GWAS efforts for complex traits and behaviors such as alcohol are limited in this respect at this time given the massive sample sizes required to detect small effects. Additionally, our study incorporated individuals from a sample enriched for risk, so it is unclear if our findings would generalize to other populations.
