variants with one another and with prominent environmental exposures, which will likely require very large sample sizes with harmonized exposures and addiction phenotypes across multiple datasets. In the future expansion of GWAS sample sizes, we emphasize the importance of including diverse ancestry groups that rival the current representation of European ancestry to address important health disparities, identifying variants that manifest under certain genetic, cultural, or environmental backgrounds and narrowing the resolution of association signals that arise from the varied linkage disequilibrium patterns across diverse populations.
