AED Effects on Subjective Feelings of Intoxication

In laboratory studies with human subjects, caffeine:

Reduced volunteers’ subjective feelings of alcohol intoxication when compared to those who drank similar quantities of alcohol without caffeine
Did not reduce alcohol’s destructive impact on volunteers’ heart rate, oxygen intake, and other physiological variables during strenuous exercise;
Adversely affected volunteers’ visual reaction time, motor coordination, and other physical skills.

Effects of energy drink ingestion on alcohol intoxication. [Link to Journal Abstract]

Can energy drinks affect the effects of alcoholic beverages? A study with users. [Link to Journal Abstract]

In laboratory studies using rats:

Alcohol made the animals more relaxed, but less able to avoid unpleasant shocks and navigate a maze
Caffeine improved the animals ability to navigate the maze and avoid the shocks
Alcohol combined with caffeine made the rats relatively alert and relaxed, but they were incompetent to avoid unpleasant shocks and navigate a maze as those receiving alcohol and no caffeine.

Effects of ethanol and caffeine on behavior in C57BL/6 mice in the plus-maze discriminative avoidance task. (Click Here)