A study published in the Journal of Adolescent Health found frequent energy drink consumers -- those who consumer such drinks six or more days a month -- were approximately three times as likely than less-frequent energy drink consumers or non-consumers to have smoked cigarettes, abused prescription drugs and been in a serious physical fight in the year prior to the survey.

Study leader Kathleen E. Miller of the University at Buffalo's Research Institute on Addictions said energy drinks typically contain three times the caffeine of a soft drink, and in some cases, up to 10 times as much.

Frequent energy drink consumers also report drinking alcohol, having alcohol-related problems and using marijuana about twice as often as non-consumers of energy drinks. They were also more likely to engage in unsafe sex.

Almost 800 Buffalo-area male and female undergraduate students participated in the study, with 39 percent reporting they had consumed at least one energy drink in the previous month.

Two-thirds of the energy drink consumers had used energy drinks as mixers with alcoholic beverages.

"It is widely, but incorrectly, believed that the caffeine in energy drinks counteracts the effects of alcohol," Miller said.