Alcohol and drug dependence tend to co-aggregate in families58,59. Based on a prior GWAS in a smaller subset of 118 COGA families23, we developed an ANYDEP phenotype that represented a diagnosis of dependence on alcohol or any illicit drug. GWAS in the COGA AA families identified novel loci on chromosomes 3, 5, and 13 while the trans-ancestral EA+AA analysis identified a locus on chromosome 1. However, these signals failed to replicate in independent samples. In addition, across the AA and EA GWAS, a total of 4 genes (AA and EA) and 4 gene sets (EA only) survived correction for multiple testing. These findings underscore the feasibility of using an aggregate substance dependence phenotype to identify underlying shared heritable influences for locus discovery.
