In this study, the Substance Use Disorders working group of the Psychiatric Genomics Consortium (PGC-SUD14) compiled the largest numbers of carefully diagnosed alcohol dependent individuals and alcohol-exposed controls to date, from both case-control and family studies. These included substantial numbers of both European ancestry (EU, N = 46,568, including 38,686 unrelated individuals) and admixed African-American ancestry (AA, N = 6,280, including 5,799 unrelated individuals) subjects. AD diagnoses were derived from clinician ratings or semi-structured interviews following DSM-IV2 criteria. Each study was subjected to stringent quality control (QC) before conducting GWAS within each population of each study, followed by a genome-wide meta-analysis. We estimated the SNP-heritability (h2g) of AD and examine the extent to which aggregate genetic variation in AD is related to traits from 45 other GWAS, including continuous measures of alcohol consumption. We also examined whether polygenic risk scores (PRS) derived from these analyses predicted alcohol dependence and related measures of problem drinking in three independent samples.
