Quick! What's the most widely used psychoactive drug in the world? Alcohol? Tobacco? Wrong--it's caffeine, the drug of choice for 89% of Americans. Does that make us a nation of drug addicts?
The caffeine debate has been perking along for years. John R. Hughes, M.D., and colleagues at the University of Vermont tested 22 coffee drinkers for signs of drug dependence. 'Me drinkers consumed three to seven cups a day of either standard or decaffeinated brew.
Without knowing which was which, 10 of the 22 "very consistently" chose the caffeine version--evidence for drug self-administration. And on days they didn't get caffeine in their brew, 40% of drinkers reported headaches, drowsiness, and fatigue.
As for adverse effects--tremulousness, stomachache, sweatiness, even ringing in the ears--they can "occur at intakes equivalent to four six-ounce cups a day," the team reports in the Archives of General Psychiatry.