The Collaborative Study on the Genetics of Alcoholism (COGA) study recruited alcohol dependent probands through substance use treatment programs at 7 sites across the United States. Probands and their family members were invited to participate, resulting in an overrepresentation of densely affected multiplex pedigrees. Control families (2 parents and 3 or more offspring over the age of 14) were also selected from a variety of community sources (e.g., driver license registries). The institutional review boards for all 7 data collection sites, and additional data analysis sites, approved the study31.
