Acute and Residual Effects of Caffeinated Beer

Inclusion Criteria: * College students, graduate students, or recent graduates * Between the ages of 21 and 30 years inclusive (as verified by valid drivers license) * Who, if a student, reports good academic standing * Have not been diagnosed with a sleep disorder * Are not daily smokers * At least occasionally in the past month, consume five drinks (for men) or more (four or more if female \[based on Flannery et al 2002\]) during a single drinking episode * Have a valid drivers license, so as to include only people who know how to drive. Exclusion Criteria: * Scores of 5 or more on a screening measure for alcoholism (the short version of the Michigan Alcohol Screening Test \[SMAST\]) * A history of counseling or treatment for chronic substance abuse by self-report * Daily smoker (to mitigate confounding of caffeine by nicotine withdrawal, or acute nicotine administration, smokers will be excluded from participation) * Current use of medications that affect the sleep/wake cycle or daytime alertness or that are contraindicated for alcohol * Presence of a health condition that contraindicates alcohol * Diagnosis of a sleep disorder (sleep apnea, narcolepsy, periodic limb movement, restless legs syndrome, circadian rhythm disorder, and insomnia) * Use of recreational drugs (e.g., marijuana) while participating in the study * Working overnight shifts * Female and pregnant, nursing, or not using reliable birth control * Participants who have traveled across two or more time zo…