Secondary analysis tested for association within the subset of cases that met criteria for early onset of alcohol dependence (≤22 years; n=454). No SNP met genome-wide significance. The SNPs with the smallest p values in the two analyses substantially overlap: 25 of the 100 SNPs with p ≤10−4 for alcohol dependence also had p ≤10−4 for early onset alcohol dependence, despite the smaller sample size (Supplemental Table 1). Notably, the odds ratios for the early onset phenotype and the dependence phenotype are very similar: of the top 199 SNPs for dependence, 166 had odds ratios for both phenotypes within ± 0.10 of each other.
