To characterize individual risk across hundreds or thousands of alleles associated with an outcome in a GWAS, genome-wide polygenic risk scores (GPS) have emerged as a way to aggregate this information into a single score. As we begin to identify GPS robustly associated with substance use and dependence, one of the critical next steps toward precision medicine will be to characterize the pathways by which risk unfolds [22]. For alcohol related outcomes, this will necessitate characterizing how specific environments moderate the likelihood that individuals carrying risky genetic predispositions will develop excessive use, problems and dependence, providing important information about targeted areas for intervention.
