Combined Effects of Alcohol and Caffeine

Combined Effects of Alcohol and Caffeine

The purpose of this study is to investigate the effects of caffeine on the self-administration of alcohol. The study will also examine the combined effects of alcohol and caffeine on behavioral performance, participant ratings of behavioral performance, and self-reported subjective effects.

The purpose of this study is to examine the effects of caffeine on alcohol self-administration. Volunteers will participate in 7 experimental sessions in which they will be given the opportunity to self-administer an alcohol + caffeine or alcohol + caffeine-placebo beverage. The first 6 sessions will involve exposure to the two beverage conditions in mixed order three times each (e.g., A, B, B, A, A, B). The seventh session will be a choice session in which the participant will make a single choice at the beginning of the session about which beverage they will consume that day. In addition to the primary outcomes of quantity of alcohol self-administered and beverage choice, three additional outcomes will be measured including: 1). indirect measures of reinforcing effects (e.g. subjective ratings of liking, well-being, take again); 2). an alcohol-sensitive behavioral measure; and 3). participant ratings of degree of behavioral impairment.

Inclusion Criteria:

• Very light or moderate consumer of caffeine (either daily or non-daily).
• Social drinker of alcohol.
• Has experience in lifetime of heavy alcohol consumption.
• Read, write, and speak English fluently.

Exclusion Criteria:

• Serious and unstable illnesses including current hepatic, renal, gastroenterologic, respiratory, cardiovascular (including ischemic heart disease, uncontrolled hypertension, and congestive heart failure), endocrinologic, neurologic (including stroke, transient ischemic attack, subarachnoidal bleeding, brain tumor, encephalopathy, and meningitis), or hematologic disease.
• Parkinson's disease, seizure disorder, or history of significant head trauma.
• Current psychiatric illness
• Pregnant or nursing women or women who are not using an effective means of birth control.