Probands were then followed about every five years regarding demography as well as alcohol, smoking and illicit drug use and related problems using questions derived from the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA) instrument. The SSAGA has validity, retest reliabilities, and cross-interviewer reliabilities of .7–.8 regarding alcohol-related items (Bucholz et al.,1994; Hesselbrock et al.,1999).
