The high-risk families were identified through a proband pair of alcohol dependent sisters. One member of the proband pair was in a substance abuse treatment facility in the Pittsburgh area at the time of recruitment. Both members of the proband pair were screened using an in-person structured interview (Diagnostic Interview Schedule) (DIS; Robins et al., 1981) to determine the presence of alcohol dependence and other Axis I psychopathology. This ascertainment strategy results in a high density of alcohol dependence (Figure 1). The DIS was also administered to all available first-degree relatives. Unavailable or deceased relatives were diagnosed by family history report. Families were excluded if the proband or her first-degree relatives met criteria for primary recurrent major depression, bipolar disorder, primary drug dependence (i.e. drug dependence preceded alcohol dependence by 1 or more years) or schizophrenia. Available spouses were diagnosed using the same methods as members of the target families.
