The effects of caffeinated vs. placebo beverage on self-reported mood state in college students

Many people rely on caffeine because of its effects. The primary purpose of the current study was to measure the effects of caffeine on current mood state, the effects of caffeine on mood dependent upon time of questionnaire administration, how caffeine and mood interact to impact attention and distraction, and if this varied by gender. A Feeling State Questionnaire (FSQ) was taken by each of the 13 participants throughout the day, before and after the administration of a soft drink containing either caffeine or placebo; furthermore it was a within subjects design meaning that each of the participants received both conditions. Previous research has indicated a calming effect associated with caffeine via becoming less emotionally distracted, and that these findings would vary by gender. Therefore, it was hypothesized that the caffeinated beverage would improve negative mood, increase positive mood, improve self-reported general attention (i. e. caffeine will aid in improving self reported concentration) and that findings would vary by gender. The results revealed a significant effect of time of the FSQ administration on both negative and positive mood. ANOVA revealed a three way interaction between caffeine condition, FSQ administration time, and gender. When aggregated across caffeine conditions, results suggested a positive effect of caffeine in females by reducing negative mood state differentially later in the day when more fatigued. Implications of results, limitations, and future research in this area are discussed