The Effects of Daily Caffeinated Energy Drink Use and Caffeine Abstinence on Sleep and Mood Among Young Adults

Caffeinated energy drinks (EDs) have become increasingly popular among young adults in the past decade, with a corresponding increase in reports of adverse events following their consumption (Reissig et al., 2009). There is a lack of controlled research on the effects of consuming EDs over an extended period of time on mood and sleep, particularly among young adults. The goal of this study was to examine the effects of three weeks of daily caffeinated EDs on mood and sleep in a sample of light caffeine users. Participants (n=36) consumed one ED each day for five weeks after one week of self-monitoring their mood and sleep. Participants consumed placebo EDs during week 2, caffeinated EDs (200 mg) during weeks 3-5, and placebo EDs during week 6. Participants completed self-report measures of mood and sleep three times per day. Sleep was also monitored with Fitbit devices. Results show that three weeks of daily caffeinated ED consumption at a low dose led to greater feelings of jitteriness and less total sleep time. Abstinence after three weeks of caffeine resulted in greater withdrawal symptoms, mood disturbances, and less total sleep time, suggesting the development of physical dependence. Tolerance to the effects of caffeine on various aspects of mood was also demonstrated. This study is among the first to show a direct causal link between prolonged daily consumption of a low dose caffeinated ED and poor sleep and mood disturbances in a sample of young adults. These findings call for further investigation of the effects of chronic ED consumption and have implications for the regulation of caffeine content in EDs.