Have You Gone Caffeine Crazy?

Are You Hooked?

There's no question that caffeine is habit-forming. Taking in as little as 100 milligrams daily, about what you get in one 8-ounce cup of non-gourmet coffee, can produce withdrawal symptoms if you abstain. "Caffeine use is so widely accepted that we've become blind to the fact that this is a mood-altering drug," says Roland Griffiths, PhD, a behavioral pharmacologist at Johns Hopkins University. "About half of regular caffeine drinkers experience withdrawal symptoms when they wake up."

Caffeine takes about 10 to 15 minutes to get into the bloodstream and peak levels can be reached in 45 minutes, according to James D. Lane, PhD, director of the Duke University Medical Center Psychophysiology Laboratory. The effects don't wear off for four hours or more. Because your body habituates itself to caffeine over time, people who use it regularly may need escalating doses to get the same effect (see "'This Is Your Brain on Caffeine'").

When regular drinkers don't get their fix, they can feel draggy, irritable, and unfocused. For about half of regular coffee drinkers, going cold turkey can trigger a full-blown withdrawal syndrome -- nausea, muscle aches, throbbing headaches. In 13 percent of cases symptoms are so severe they interfere with functioning. "Caffeine withdrawal can be terrible, like having a bad case of the flu," says Dr. Juliano.

Some people can get trapped in what experts call the "stimulant-sedative loop." Caffeine causes insomnia, so they pop a pill to sleep at night. When they wake up, it takes caffeine to stay alert during the day. This disturbs the body's normal sleep/wake cycle.

A slew of recent studies tout coffee's potential to prevent liver and colon cancer, heart disease, type 2 diabetes, and Parkinson's disease. Scientists attribute these benefits to the antioxidants and minerals contained in coffee beans -- in short, it's other stuff in coffee, not the caffeine, that provides them. These compounds help the liver process blood sugar, which may be why drinking coffee seems to reduce the risk of diabetes. Antioxidants may also play a role in preventing heart disease and liver and colon cancer by curbing the cell damage that contributes to the development of these diseases. Coffee, in fact, is the number one source of antioxidants in our diets, according to a 2006 University of Scranton study. "Nothing else comes close," says Joe Vinson, PhD, a professor of chemistry at the university, who ran this research.

Caffeine itself -- from coffee and other sources -- has health benefits, too. It boosts energy, improves alertness and reaction time, helps us learn better, increases stamina, and fires up the metabolic furnace. Two recent studies reveal it can even help memory: In a 2005 Austrian study, 100 milligrams a day increased activity in the part of the brain responsible for short-term memory and improved performance on a memory test. And in February, Dutch researchers found that three cups of coffee a day slowed the loss of mental function in men.