The original Collaborative Study of the Genetics of Alcoholism (COGA) study recruited probands through inpatient or outpatient substance-use treatment programs at seven sites across the United States and were included in the study if they met diagnostic criteria for alcohol dependence specified in the Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R; American Psychiatric Association, 1987) as well as criteria for alcoholism specified by Feighner and colleagues (1972). Control families (two parents and three or more offspring over the age of 14) were also selected from the community. All participants were interviewed across various psychiatric domains using the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA-IV) (Bucholz et al., 1994). Adolescents (younger than 18 years of age) were interviewed with a modified version of the SSAGA-IV that incorporated age-appropriate wording. A more detailed description of the COGA study is included elsewhere (Begleiter et al., 1995). The institutional review boards for all seven data collection sites, and additional data analysis sites, approved the study.
