Data for this study were drawn from the Collaborative Study on the Genetics of Alcoholism (COGA), a multi-site, large, multigenerational family study that aims to identify genetic influences on alcohol dependance and related psychiatric phenotypes (Begleiter et al., 1995; Edenberg, 2002). Probands were identified through alcohol treatment programs at seven U.S. sites and were invited to participate if they had a sufficiently large family (usually sibships of more than three with parents available) with two or more members in the COGA catchment areas. Comparison families were also recruited from the community. Data collection for COGA started in 1991 (Phase I) when adults in the target extended families were invited to complete the Semi-Structured Assessment for the Genetics of Alcoholism, a comprehensive interview that assesses demographic factors, alcohol use disorders, and a variety of psychiatric phenotypes (Bucholz et al., 1994). Participants were followed up about 5 years after they completed the first assessment (Phase II). The average time to follow up at Phase II was 5.7 years. Participants also completed questionnaires, including the Perceived Social Support from Family/Friends Scale at Phase
