In our Cox model analyses, PRS was not significantly associated with AOO of AUD in the AA sample (although predictive ability using ROC was similar in the two groups using primarily clinical variables). Recent studies (55) show that PRSs for bipolar disorder derived from EA subjects are reasonably predictive when applied to East Asian subjects but less so when applied to AA populations. It is well established that linkage disequilibrium blocks (units of correlated genetic markers) are smaller in AA subjects than in other populations. This is related to the history of the human species, which extends an order of magnitude longer on the African continent than in other areas of the world (56). Thus, there are different allele frequencies and greater variation in allele frequency in AA subjects compared with those of other ancestries. The reliability of PRS developed from other ancestral groups is consequently less in AA subjects. Because PRS would currently be less useful for AA subjects than for EA subjects, questions arise regarding inequities in clinical application (57). One solution is increased emphasis on collection of
