The Collaborative Study on the Genetics of Alcoholism (COGA) is a multi-site project, with the goal of identifying genes contributing to alcoholism and related phenotypes. Probands were identified through inpatient or outpatient alcohol treatment programs at six sites around the United States and were invited to participate if they had a sufficiently large family (usually sibships > 3, with parents available) with two or more members living in a COGA catchment area (Begleiter et al., 1995). The institutional review boards of all participating centers approved the study. Written consent was obtained from all study participants. Additional details about the study have been published previously (Foroud et al., 2000, Edenberg et al., 2004, Reich et al., 1998). The sample has n=1905 individuals (1205 cases and 700 controls). The sample is 46% female; 74% of the sample self-identified as European American, and 26% as African American.
