New look at caffeine cravings.

Caffeine, ubiquitous in coffee, tea and colas, ranks as the most widely used psychoactive drug in the world. However, researchers disagree on whether people can get hooked on it.

A preliminary study now suggests that some coffee drinkers exhibit three signs of caffeine addiction: They seek out the drink for caffeine's stimulating and pleasing effects; they experience withdrawal symptoms such as drowsiness, fatigue and headaches; and they report adverse effects of caffeine consumption such as stomachaches, earaches, trembling and profuse sweating. These same coffee fans lack other key signs of drug dependence, including unsuccessful efforts to control their caffeine use, and tolerance to caffeine's behavioral effects.

Psychiatrist John R. Hughes and his co-workers at the University of Vermont in Burlington studied 22 healthy adults who normally drank three to seven cups of caffeinated coffee each day. Given a choice, 10 of the volunteers consumed significantly more of an unlabeled caffeinated coffee than an unlabeled decaffeinated coffee over a two-day test period. Most caffeine seekers also reported adverse caffeine effects and withdrawal symptoms. Even so, labeling heavy caffeine use as "drug dependence" remains controversial, the researchers conclude in the July Archives of General Psychiatry.