Mixing alcohol and energy drinks increases the urge to drink more than drinking alcohol alone, according to a new study from Australia.
The findings suggest that people who mix alcohol and energy drinks may end up drinking more alcohol than they intended, said the study's lead author.
"Obviously these findings are not going to deter young people from drinking if they want to get drunk, but they need to be mindful that they may be unwittingly putting themselves at a greater risk of accidents and injuries because they end up drinking more than they had intended," Rebecca McKetin said in an email.
The study results are similar to those of research published by a US group last year, write McKetin and her coauthor Alice Coen, who are both with the Australian National University's Center for Research on Ageing, Health and Well-being in Canberra.
"We normally think of alcohol as a depressant, but it also has a stimulant effect, and it is this stimulant effect that is most strongly related to how much we like alcohol, and whether we want to keep drinking," McKetin said. "Energy drinks contain caffeine. Caffeine, being a stimulant, tends to bring out the stimulant effects of alcohol intoxication. It may be this that causes energy drinks to increase the desire to keep drinking alcohol."
For the new study, she and Coen recruited 75 participants between the ages of 18 and 30 years. The participants were assigned to drink either vodka mixed with soda water or vodka mixed with a popular energy drink.
Both cocktails also contained some fruit juice. The participants were unaware of which cocktail they drank.
The participants answered a series of questions before they drank their cocktail and again 20 minutes afterward.
Those who drank the cocktail containing vodka and the energy drink reported a greater urge to drink afterwards than those who drank the cocktail of vodka and soda water. That was especially true among the test subjects who had higher blood alcohol levels, the researchers found.