Caffeinated alcohol use and expectancies for caffeine versus alcohol

Background: Caffeinated alcoholic beverage (CAB) use is related to alcohol-related risk. Limited research has examined outcome expectancies and CAB consumption. Objectives: This study tested the predictive utility of caffeine and alcohol expectancies in CAB use outcomes (i.e. quantity, frequency, and alcohol-related harms). Methods: Participants were 419 (302 women) alcohol and caffeine users from a mid-sized urban university. Data collection occurred between August 2010 and December 2011. Participants completed measures of caffeine and alcohol expectancies, alcohol problems, alcohol use, and CAB use. Results: Caffeine and alcohol expectancies contributed uniquely to approximately 12% of the variability in quantity, 8% in frequency, and 16% in problems. When examined separately, alcohol expectancies explained approximately 10% to 11% of the variance, whereas caffeine expectancies accounted for 6% of the variance in CAB use quantity. For CAB use frequency, alcohol and caffeine expectancies accounted for about 8% and 4%, respectively. Alcohol expectancies accounted for 12% to 14% of variance, whereas caffeine expectancies accounted for 4% to 6% in alcohol-related harms. Conclusions/ Importance: The present study sought to address a gap in the literature regarding the contributions of expectancies in the prediction of CAB use. Our findings provide support for the predictive utility of both caffeine and alcohol expectancies in accounting for individual variability in CAB use but alcohol expectancies may exert greater impact on use patterns. Inclusion of both types of expectancies in larger theoretical frameworks may be beneficial in gaining a more complete and deeper conceptualization of this risky behavior.