Data were collected from 1287 probands and 7318 relatives of probands who participated in the Collaborative Study on the Genetics of Alcoholism (COGA), a high-risk family study of alcohol dependence (Foroud et al., 2000; Reich et al., 1998). Probands were recruited from treatment settings in 6 catchment areas (Farmington, CT; Brooklyn, NY; Indianapolis; IN, St. Louis, MO; Iowa City, IA; and San Diego, CA) and were required to meet criteria for DSM-III-R alcohol dependence ( American Psychiatric Association, 1987), Feighner definite alcoholism (Feighner et al., 1972), and to have at least two first-degree relatives available for study. The institutional review board at each site approved the protocol, and written informed consent was obtained from all subjects. Details about ascertainment are available from previous studies (Bucholz et al., 1996; Reich et al., 1998). The sample was 51% male, 74% non-Hispanic white, 17% African American, 6% Hispanic white, and 3% other ethnicity, with a mean age of 40.2 (sd = 13.6). Forty-nine percent of participants were married at time of interview, 28% had never been married, and 23% were widowed, separated, or
