Phone screens determined initial eligibility based on the following criteria: age 19–21; at least 1 heavy drinking episode (4+ drinks for women/5+ drinks for men) in the last month; a Brief Michigan Alcohol Screening Test (MAST) score <10, with no history of treatment for alcohol use or current attempts to reduce drinking; a Fagerstrom Test for Nicotine Dependence (FTND) score <6; no prior adverse reactions to venipuncture; no current illicit drug use other than cannabis; and no medical conditions or medications for which alcohol was contraindicated. Participants then completed an in-person visit that included informed consent, verification of eligibility criteria, height and weight measurements, baseline questionnaires, DNA collection via saliva sample, and assessment of 90-day alcohol and substance use. After a physician further confirmed medical eligibility, participants were scheduled for alcohol administration sessions.
