Data were from participants in the ongoing prospective cohort of the Collaborative Study of the Genetics of Alcoholism (COGA), a multi-site family study which began in 1989 with the purpose of identifying genes that increase the risk for AUDs. Families were identified through probands in treatment for alcoholism at 6 sites in the U.S. Probands and their first-degree relatives were interviewed with a comprehensive, structured interview, the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA) (31, 32), and in families where 2 or more first-degree relatives were also affected, additional branches of the family were recruited to the study. Comparison families recruited from a variety of sources (e.g., dental clinics, drivers’ registries) participated in the same protocol. Because these families were intended to represent a subset of the general population, family members were not excluded if they met criteria for an AUD or other psychiatric disorder. Further details about the study have been published (33, 34).
