Energy drinks combined with alcohol (AmEDs) were once available for purchase as a premixed beverage, until 2010 when the U.S. Food and Drug Administration determined that the combination was unsafe. However, the popularity of AmEDs continues to rise, fueled by private consumers and bartenders. There are a variety of risks associated with AmEDs, including a greater chance of binge drinking than with alcoholic beverages alone. This study investigated whether consuming high-caffeine energy drinks mixed with alcohol results in a greater desire to drink alcohol than alcohol alone.

Researchers invited 26 adult social drinkers (13 males, 13 females) to attend six double-blind sessions that involved drinking alcohol and energy drinks, alone and in combination. On each test day, participants received one of six possible doses: 1) vodka + decaffeinated soft drink, 2) vodka + medium energy drink, 3) vodka + large energy drink, 4) decaffeinated soft drink, 5) medium energy drink, and 6) large energy drink. After each session, the participants rated their desire for alcohol and their breath alcohol concentration was measured.

Results showed that alcohol alone increased the subjective "desire for more alcohol" compared to placebo doses. AmEDs increased the desire for more alcohol beyond that observed with alcohol alone. In summary, this study provides laboratory evidence that AmEDs lead to a greater desire to drink alcohol than the same amount of alcohol consumed alone, and are consistent with animal studies showing that caffeine increases the rewarding and reinforcing properties of alcohol.