Despite contrary marketing claims, high-caffeineated beverages have little or no effect on the neuromotor impairment caused by alcohol, BU Today reported Jan. 19.

To measure the effects of caffeine and alcohol on motor skills, investigators from the Boston University (BU) School of Public Health and Brown University’s Center for Alcohol and Addiction Studies randomized 127 young adults to one of four treatment conditions: beer with or without caffeine, or nonalcoholic beer with or without caffeine. None of the participants screened positive for alcohol dependence, but all reported participating in binge drinking.

After consuming the beverages until those drinking alcohol reached a blood alcohol level above the legal limit for driving, participants in each group were assessed on driving performance (via simulator) and on sustained attention/reaction time.

According to results, while alcohol significantly impaired driving, attention, and reaction skills, the addition of caffeine did nothing to improve driving performance and had only a barely measurable effect of attention/reaction scores.

Nontraditional marketing approaches suggest mixing alcohol with caffeine will “enhance attention, endurance, performance, weight loss, and fun, while reducing performance decrements from fatigue from alcohol,” said the study authors, who were led by BU Professor of Community Health Jonathan Howland, Ph.D.

“Regulators should scrutinize energy drink and CAB [caffeinated alcoholic beverage] advertising as it relates to promoting safety-related expectancies.”

The study was published in the February 2011 issue of the journal Addiction.