Using procedures approved by the University of California, San Diego (UCSD), Human Research Protections Committee, the data described below were gathered during several phases in the course of the SDPS. Between 1978 and 1988, each year the original probands were identified from a mailed questionnaire that asked students to report their demography and substance use patterns and problems (Schuckit and Gold, 1988). To be eligible for the next stage of the study, a student had to be age 18 to 25 years (old enough to give consent but not too old as to have passed through the usual age of onset of alcohol dependence), with exclusions for potential participants who ever met criteria for alcohol or illicit drug dependence, bipolar disorder or schizophrenia using the Diagnostic and Statistical Manual (DSM) criteria (e.g., American Psychiatric Association, 1994). Appropriate probands were originally evaluated using alcohol challenges where, on rising, peak and falling BACs (peak BAC averaged about 60 mg/dl), they reported subjective feelings of intoxication, and were evaluated for changes in standing steadiness (body sway), and, depending on the specific paradigm, the
