In this study, we sought to harness the phenotypic richness of the high density alcohol dependent families recruited as part of the Collaborative Study on the Genetics of Alcoholism (COGA) to perform a series of complementary analyses designed to identify variation contributing to the risk of AD. Our primary GWAS focused on DSM-IV AD diagnosis, a clinically validated measure of pathological drinking that is commonly used in GWAS 6. We also conducted secondary GWAS of AD severity defined as the count of these criteria (range 0-7), as this quantitative phenotype has been shown to facilitate identification of GWS loci over the binary diagnostic measure of DSM-IV AD (e.g.,21). In tertiary analyses, we conducted exploratory GWASs of the seven individual DSM-IV AD criteria, in order to assess which criteria were the most significant contributors to the overall findings observed for DSM-IV AD diagnosis and criterion count, and further, examine whether novel loci emerged for individual criteria. To identify common variants associated with these phenotypes, a GWAS was performed in the European American (EA, n=1,114 families; “EA GWAS”) subsample of COGA, followed
