Individual measures for the twin fathers were drawn from the Diagnostic Interview Schedule (DIS-III-R; Robins et al., 1989), which was administered in 1992 (see Tsuang et al., 1996, 1998); DSM-III-R substance dependence diagnoses were created from the DIS. The offspring and spouses of the twins in both projects completed a telephone adaptation of the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA; Bucholz et al., 1994) in 2001–2004, from which a DSM-IV alcohol dependence diagnosis was created.
