The study samples included our GWAS samples (Yale-UPenn) (N=5,543) and the public samples (SAGE: phs000092.v1.p1, N=4,012). Sample characteristics are shown in Table 1. The Yale-UPenn sample was recruited for studies of the genetics of drug (opioid or cocaine) or alcohol dependence. The SAGE sample consists of the Collaborative Study on the Genetics of Alcoholism (COGA) (Edenberg and Foroud, 2006, Edenberg, 2002), the Family Study of Cocaine Dependence (FSCD) (Grucza et al., 2008), and the Collaborative Genetic Study of Nicotine Dependence (COGEND) (Bierut, 2007) samples. We obtained the SAGE data via dbGAP.
