The subjects are offspring of probands from the SDPS who, to optimize the number of subjects likely to have experience with alcohol, were at least 15 years old at the time of their most recent interview. The fathers of these offspring had originally been selected between 1978 and 1988 as 18- to 25-year-old drinking Caucasian men who responded to questionnaires mailed to randomly chosen students and non-academic staff at the University of California, San Diego (Schuckit & Gold, 1988; Schuckit & Smith, 2000). All 453 original subjects were evaluated using an initial baseline interview and followed up at 10 years (T10 with 99% retention), 15 years (T15 with 97%), 20 years (T20 with 95% retention) and during the ongoing 25 year followup (Schuckit & Smith, 1996, 2000). As subjects married and had children, these relatives entered the protocol, with participation rates that also exceeded 95% at the 20-year follow-up.
