Mounting scientific evidence shows that jokes about caffeine withdrawal are no joke at all -- and it doesn't take much to get hooked.
"Some people say it's all in your head," says Roland Griffiths, a caffeine researcher at the Johns Hopkins School of Medicine. "We're able to show, based on a number of rigorous studies, that it's real and biological."
In the most comprehensive survey of caffeine withdrawal research to date, Griffiths and a colleague pored over 170 years of studies and concluded that regular consumption of one small cup of coffee -- 100 milligrams of caffeine -- is enough to trigger such withdrawal symptoms as headaches, fatigue and irritability.
For serious caffeine junkies, going cold turkey can be even more traumatic. The latest analysis, published last month in the journal Psychopharmacology, found that some experience flulike symptoms such as muscle pain, nausea and vomiting when they go off caffeine. Thirteen percent of people weathering withdrawal have to call off work or cancel daily chores.
Some psychologists are even pushing the American Psychiatric Assn. to classify caffeine withdrawal as a bona fide mental disorder in the next edition of its Diagnostic and Statistical Manual of Mental Disorders.
If that happens, it probably will be in part because of Griffiths. The 58-year-old psychologist is regarded as one of the country's leading investigators of caffeine and its effects.
Generally safe, caffeine is the most popular mind-altering drug in the world, consumed by 80% of Americans. That alone made it worth investigating, says Griffiths, who became interested in the drug in the 1980s.
As a researcher who also studies nicotine, cocaine and other often-abused drugs, he also realized that caffeine might be a good model for analyzing the addiction process. "It's not cocaine," Griffiths explains. Yet "it controls behavior."
Just how much remains hotly debated. The American Psychiatric Assn. doesn't recognize caffeine as a drug that causes dependence. But Griffiths says anybody who requires convincing need only hang out at a Starbucks some morning -- as Griffiths has done -- to watch the regulars roll in like clockwork.
"People get dependent on caffeine," says Griffiths. "The question is: How does the drug do that? What kind of biological mechanism is it hijacking? It becomes this really interesting puzzle to figure out."
Caffeine acts quickly. "Soon after you finish your cup of coffee or tea, caffeine will be present in virtually every cell of your body," Bennett Weinberg and Bonnie Bealer note in "The World of Caffeine: The Science and Culture of the World's Most Popular Drug."
Griffiths' research has shown that people begin to feel caffeine's mood-altering effects after ingesting as little as 10 milligrams -- "just a sip of coffee."
The drug disappears quickly -- typically within 12 to 24 hours. This, says Griffiths, explains why coffee is so often a morning ritual: "People are actually waking up in withdrawal." Griffiths and other caffeine researchers insist that they have nothing against the drug, which has undoubtedly saved lives and careers by helping drowsy drivers, soldiers, aviators, students and machine operators stay awake. Recent research even hints that caffeine helps protect against gallstones and Parkinson's disease.
"You don't lose your job, your friends or your money by taking caffeine," says American University psychologist Laura Juliano, who collaborated with Griffiths on the latest review of withdrawal research. "That's not to say that people don't do pretty extreme things sometimes to get it," she adds.
Some caffeine users want to stop but can't. To understand why, Griffiths launched a program in 2001 to study and treat caffeine dependence. His little-publicized clinic may be the only one of its kind in the nation.
The 59 participants keep a diary of caffeine use and have monthly therapy sessions. Saliva tests help determine whether they're sticking to the program.
For many, the program works. But some people find they can't -- or don't want to -- quit. Griffiths isn't surprised. After all, he says, there's a reason why caffeine has been popular in so many cultures over the centuries. "It's a great drug," he says.