The acute effects of caffeinated versus non-caffeinated alcoholic beverage on driving performance and attention/reaction time.
OBJECTIVE
Marketing that promotes mixing caffeinated 'energy' drinks with alcoholic beverages (e.g. Red Bull with vodka) targets young drinkers and conveys the expectation that caffeine will offset the sedating effects of alcohol and enhance alertness. Such beliefs could result in unwarranted risk taking (e.g. driving while intoxicated). The aim of this study was to assess the acute effects of caffeinated versus non-caffeinated alcoholic beverages on a simulated driving task and attention/reaction time.


METHODS
We conducted a 2 × 2 between-groups randomized trial in which participants were randomized to one of four conditions: beer and non-alcoholic beer, with and without caffeine added. Caffeine was added in the same proportion as found in a commercially available caffeinated beer (69 mg/12 oz of beer at 4.8% alc. by vol).


METHODS
Participants were 127 non-dependent, heavy episodic, young adult drinkers (age 21-30) who were college students or recent graduates. The target breath alcohol level was 0.12 g%.


METHODS
Driving performance was assessed with a driving simulator; sustained attention/reaction with the Psychomotor Vigilance Task (PVT).


RESULTS
Across the driving and attention/reaction time we found main effects for alcohol, with alcohol significantly impairing driving and sustained attention/reaction time, with mainly large statistical effects; however, the addition of caffeine had no main or interaction effects on performance.


CONCLUSIONS
The addition of caffeine to alcohol does not appear to enhance driving or sustained attention/reaction time performance relative to alcohol alone.
Department of Community Health Sciences, Boston University School of Public Health, Boston, MA 02118, USA. jhowl@bu.edu
Jonathan
J
Howland
Damaris J
DJ
Rohsenow
J Todd
JT
Arnedt
Caleb A
CA
Bliss
Sarah K
SK
Hunt
Tamara Vehige
TV
Calise
Timothy
T
Heeren
Michael
M
Winter
Caroline
C
Littlefield
Daniel J
DJ
Gottlieb
D000328:Adult; D000428:Alcohol Drinking; D000435:Alcoholic Intoxication / Q000523:psychology; D001288:Attention / Q000187:drug effects*; D001334:Automobile Driving; D001515:Beer; D002110:Caffeine / Q000494:pharmacology*; D002492:Central Nervous System Depressants / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D004347:Drug Interactions; D000431:Ethanol / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D010919:Placebos; D011597:Psychomotor Performance / Q000187:drug effects; D011930:Reaction Time / Q000187:drug effects*; D013334:Students; D055815:Young Adult
D002492:Central Nervous System Depressants; D000697:Central Nervous System Stimulants; D010919:Placebos; D002110:Caffeine; D000431:Ethanol