COGA recruited AD probands from inpatient and outpatient AD treatment facilities in seven sites. Community-based families were also recruited from a variety of sources26. Institutional review boards from all seven sites approved the study and all participants provided informed consent. COGA participants were administered the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA), a poly-diagnostic interview 27,28. Individuals below age 18 were administered the child version of the SSAGA, the C-SSAGA. If an individual was interviewed more than once, data from the interview with the maximum total number of endorsed DSM-IV AD criteria were utilized.
