GRS generated for alcohol problems (N=4304) only predicted 0.6% of the variance in a similar measure in an independent sample. Despite relying on a smaller discovery sample (COGA, N=1788), our findings are consistent with these estimates. Nonetheless, the small sample size of the discovery set limits the accuracy of predicted SNP effect sizes and likely influenced our ability to generate GRS that might be reliable predictors of alcohol involvement in independent samples.
