Family and twin studies have shown that the risk of stimulant use disorder is proportional to the degree of relatedness to an affected relative1,7. The heritability of stimulant use disorder (excluding cocaine) has been estimated to be 0.40–0.428,9. Although a genome-wide association study (GWAS) of methamphetamine dependence yielded no significant findings, the sample of 580 individuals was likely insufficient to detect associations with variants of modest effect10. We performed a GWAS for stimulant dependence in a discovery sample of 5681 individuals of European ancestry (EA) and 5758 of African ancestry (AA) and, after testing the top-ranked findings in an independent dataset with 3405 AA and 8185 EA individuals, identified two genome-wide significant (GWS) associations. These results provide insight into the biological basis of stimulant dependence.
