University students drinking energy drinks and alcohol are more likely to engage in casual sex, according to new research.

"Mixing energy drinks with alcohol can lead to unintentional overdrinking because the caffeine makes it harder to assess your own level of intoxication," Kathleen E. Miller, senior research scientist at the Research Institute on Addictions of the University of Buffalo in New York, US, and author of the study, said in a press release last week.

Caffeinated cocktails "have stronger priming effects than alcohol alone," she adds. "In other words, they increase the craving for another drink, so that you end up drinking more overall." The study included 648 participants, mostly under the age of 21, enrolled in their first or second years at a large public university.

According to the study's findings, 29.3 percent of sexually active students reported drinking caffeinated cocktails during the month prior to the survey. At their most recent sexual encounter, 45.1 percent of the participants reported having a casual partner, 24.8 percent reported having been intoxicated, and 43.6 percent reported that they did not use a condom.

The findings will be published in the Journal of Caffeine Research.

In another study from the same university, researchers discovered that energy drinks mixed with alcohol contribute to higher impulsivity and stimulation in the drinker, which they say can correlate with riskier behavior. Results of the new study were published the journal Alcoholism: Clinical & Experimental Research.