A new study that analyzes some 170 years' worth of research concludes that caffeine withdrawal is very real — producing enough physical symptoms and a disruption in daily life to classify it as a psychiatric disorder. Researchers are suggesting that caffeine withdrawal should be included in the next edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM), considered the bible of mental disorders.
"I don't think this means anyone should be worried," says study researcher Roland Griffiths, PhD, professor of psychiatry and neuroscience at Johns Hopkins School of Medicine. "What it means is that the phenomenon of caffeine withdrawal is real and that when people don't get their usual dose, they can suffer a range of withdrawal symptoms."
His research, published in the October issue of Psychopharmacology, analyzes 66 previous studies on the effects of caffeine withdrawal.
One Coffee Sets the Stage
Griffiths' analysis shows as little as one cup of coffee can cause an addiction, and withdrawal from caffeine produces any of five clusters of symptoms in some people:
- Headache, the most common symptom, which affects at least of 50 percent of people in caffeine withdrawal
- Fatigue or drowsiness
- "Unhappy" mood, depression, or irritability
- Difficulty concentrating
- Flu-like symptoms such as nausea, vomiting, muscle pain, and stiffness.
A new revelation in Griffith's analysis may be what upgrades caffeine withdrawal from its current "more study is needed" status to "disorder" status: These withdrawal symptoms are severe enough in about one in eight people to interfere with their ability to function on a day-to-day basis.
"The withdrawal symptoms can be mild or severe, but it's estimated that 13 percent of people develop symptoms so significant that they can't do what they normally would do — they can't work, they can't leave the house, they can't function," he says.
Interference, Not Just Symptoms
That's key for inclusion in the DSM, says John Hughes, MD, a University of Vermont psychiatrist and addiction specialist who serves as a medical consultant for the book.
"Caffeine withdrawal was proposed for DSM-IV [the current edition of DSM], but the major objection to including it as a disorder was an absence of good data showing clinical significance," says Hughes, who was not involved in Griffiths' study. "Not only do you have to show it produces symptoms, but you have to show that those symptoms can interfere with daily function."
This study, co-authored by American University researcher Laura Juliano, PhD, does that, says Hughes. "It shows very nicely that the effects of caffeine withdrawal are consistent, that several symptoms are of large magnitude, and that a minority of people cannot perform daily functions when they go without caffeine," he tells WebMD.
Their study shows no difference in withdrawal symptoms based on the source of caffeine, which includes coffee and sodas, some teas, chocolate, and medications such as Excedrin and NoDoz. "Caffeine is caffeine, from a pharmacologic point of view," says Griffiths.
In the U.S., average daily caffeine intake is about 280 milligrams — what's in two mugs of coffee or three to five cans of soft drinks. Up to 90 percent of people regularly use caffeine, and about 100 milligrams is enough to trigger withdrawal symptoms, says Griffiths.
Should You Quit?
Still, both experts say just because caffeine withdrawal can produce symptoms doesn't mean it's dangerous.
"I'm hesitant to even call caffeine an 'addiction,' because addiction has to do with the inability to stop or control," says Hughes. "Most people can stop drinking coffee, even if they have symptoms when they do."
Griffiths agrees. "The fact that caffeine produces physical dependence isn't necessarily grounds in and of itself to quit," he says. "But if you want to, the best way is with a gradual withdrawal — just slowly change the proportion of caffeinated and decaffeinated coffee until you're only drinking decaf. Don't stop abruptly; that will likely cause more symptoms."
The real message of Griffiths' findings: "It's that people should realize the possibility that caffeine withdrawal may be responsible for some symptoms," says Hughes. "If you have recurring headaches or fatigue, you really to think that it may be due to caffeine withdrawal."
SOURCES: Juliano, L. Psychopharmacology, October 2004. Roland Griffiths, PhD, professor of psychiatry and neuroscience, Johns Hopkins School of Medicine, Baltimore. John Hughes, MD, professor, department of psychiatry, psychology and family practice, University of Vermont, Burlington.
By Sid Kirchheimer
Reviewed by Michael W. Smith, MD
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