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