Many people mix energy drinks with alcohol to counteract the sedative nature of alcohol, tricking users into feeling more awake and less drunk than they really are.

However, when researchers from the University of Portsmouth and the Federal University of Santa Maria in Brazil tested the effects of taurine, a key ingredient of many energy drinks, and alcohol on social and fear responses in zebrafish, they found that taurine seemed to increase the fear-reducing properties of alcohol, but also affected social communication.

This study is the first to show that the two together may be exacerbating some of the negative effects of binge drinking; that is reduction of fear and problems in social communication while intoxicated, which collectively increase the risk of fighting, violence and participation in risky behaviours, says Dr Matt Parker, Co-author of the study.

Binge drinking and general alcohol misuse is a key problem across the world, with the numbers of hospital admissions resulting from illness or injury following intoxication costing the millions per year. Alcohol reduces our inhibitions, and in low doses can cause relaxation and euphoria. However, in higher doses, this low inhibition can cause problems with fighting or risky behaviour.

These data appear to suggest that mixing alcohol and taurine might be a factor in increasing some of the negative effects of alcohol. People should be aware that drinking energy drinks in combination with alcohol may impair their judgment, and should do so with caution, concludes Dr Parker.