It's official -- you really do need that coffee in the morning and if you don't get it, you really are in withdrawal.
As little as one cup of coffee a day can produce caffeine addiction, researchers at Johns Hopkins University in Baltimore said last week.
"Caffeine is the world's most commonly used stimulant, and it's cheap and readily available so people can maintain their use of caffeine quite easily," said Roland Griffiths, a professor of psychiatry and neuroscience who led a review of 170 years' worth of studies on caffeine.
"The latest research demonstrates, however, that when people don't get their usual dose they can suffer a range of withdrawal symptoms, including headache, fatigue and difficulty concentrating. They may even feel like they have the flu with nausea and muscle pain."
Griffiths and colleagues are pressing for caffeine addiction to be included in the Diagnostic and Statistical Manual of Mental Disorders, considered the bible of mental disorders, as well as other references.
He and Laura Juliano of American University in Washington looked at 57 experimental studies and nine surveys to validate what any coffee drinker could have said -- skipping a cup causes fatigue, grumpiness and often severe headaches.
The study was reported in the October issue of the journal Psychopharmacology.