COGA is a multi-site project, with the goal of identifying genes contributing to alcoholism and related phenotypes. Probands were identified through inpatient or outpatient alcohol treatment programs at six sites around the United States and were invited to participate if they had a sufficiently large family (usually sibships >3 with parents available) with two or more members in a COGA catchment area [Begleiter et al., 1995]. The institutional review boards of all participating centers approved the study. Written consent was obtained from all study participants. Additional details about the study have been published previously [Reich et al., 1998; Foroud et al., 2000; Edenberg et al., 2004]. All individuals aged 18 or older were interviewed using the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA) [Bucholz et al., 1994; Hessel-brock et al., 1999]. Alcoholism was defined by the presence of a DSM-IIIR alcohol dependence diagnosis [Diagnostic and Statistical Manual of Mental Disorders: IIIR, 1987], plus definite alcoholism according to Feighner Criteria [1972]. The SSAGA makes a diagnosis of childhood conduct disorder according to DSMIII-R through retrospective report of behavioral problems evidenced
