Caffeine consumption, expectancies of caffeine-enhanced performance, and caffeinism symptoms among university students.

The expectancies paradigm developed in alcohol research was used to study caffeine consumption and signs of caffeinism in two groups of college students. A survey questionnaire was developed to gather self-report data on expectations of caffeine-enhanced performance (EP-CAFF), level of beverage caffeine consumed daily, and DSM-111 caffeinism signs reportedly experienced after consumption of caffeinated beverages. A positive association between EP-CAFF and both caffeine consumption and caffeinism signs was predicted. In both initial (n = 527) and cross-validation (n = 270) samples, significant correlations between EP-CAFF scores and both caffeine consumption and caffeinism symptoms were found. A small, but statistically significant, relationship was also found between caffeinism symptoms and both alcohol consumption and cigarette smoking. Of the 797 subjects in the combined sample, 151 (18.9%) endorsed five or more DSM-III caffeinism signs. Subjects endorsing five or more signs of caffeinism scored higher on the EP-CAFF scale, and consumed more caffeine and alcohol in both studies and smoked more cigarettes in study one--but not in study two--than did subjects who endorsed fewer than five caffeinism signs. Results support the utility of extending the expectancies model of substance use motivation from alcohol to caffeine.