Antagonistic effects of caffeine and alcohol on mental performance parameters.

Scientific experiments done so far allow no clear conclusions about the popular belief that freshly brewed coffee can offset the debilitating effects of alcoholic intoxication. This question was addressed using a computer-controlled and subject-paced rapid information processing task (RIP) which was shown earlier to be sensitive to psychoactive substances. Nine male students were tested in a Latin square design before and after the intake of 3.3 mg/kg caffeine (or placebo) followed by 0.7 g/kg alcohol (or placebo). Whereas the mean RIP-task processing rate and the mean reaction time were impaired by alcohol and improved by caffeine, no changes were observed after the combination of alcohol and caffeine. Thus, it was concluded that under the tested conditions, caffeine was able to offset the debilitating effects of alcohol.