Caffeine is the world’s most commonly used stimulant. It’s inexpensive, it’s easily obtained and aside from the most popular source, coffee, it's also in many soft drinks and teas. The average daily intake of caffeine in the United States is about 280 milligrams, which is the equivalent of about one or two cups of coffee or three to five cans of soda, enough to cause an addiction. Caffeine withdrawal symptoms can range anywhere from mild to debilitating.
Withdrawal from caffeine can cause drowsiness and fatigue, making you reach for that cup of coffee once again in order to offset symptoms. Feeling tired in the morning and needing that cup of coffee to wake up may simply be a sign of caffeine withdrawal. Fatigue may affect your ability be competent at work or cause you to miss work entirely. Such sluggishness may make you unable to complete necessary tasks such as homework or interfere with responsibilities such as caring for your children.
According to a study by researchers at Johns Hopkins University School of Medicine, caffeine withdrawal causes headaches in at least 50 percent of people. The headaches may be mild or severe. Michael Kuhar, chief of the division of neuroscience at the Yerkes National Primate Research Center at Emory University in Atlanta, Georgia, explains that headaches occur because caffeine blocks receptors in the brain that can dilate blood vessels. These headaches are often described as diffuse, gradually developing into a sharp, throbbing pain.
Withdrawal symptoms such as moodiness, irritability, discontent, depression and decreased feelings of well-being are often reported. Such symptoms may be mild or can be significant enough in some people to cause them to be unable to function. They may not be able to work or even leave the house. It is estimated that 13 percent of people suffering from caffeine withdrawal develop symptoms this extreme.
Caffeine withdrawal may also affect your ability to concentrate, making performing your daily tasks difficult or impossible. Focus at work or school may be an effort. People have reported making multiple costly mistakes at work, an inability to complete homework, do normal recreational reading and an overall feeling of dullness or fogginess.
The flu-like symptoms of nausea, vomiting, muscle pain and stiffness, hot and cold spells and a heavy feeling in the arms or legs have also been reported and may be mistaken for another cause, such as a viral infection. In rare cases caffeine withdrawal may be totally incapacitating.
Roland Griffiths, PhD, professor of psychiatry and neuroscience at Johns Hopkins School of Medicine has done analysis of 66 previous studies on the effects of caffeine withdrawal. His report, published in the October 2004 issue of Psychopharmacology, shows that the onset of symptoms from the withdrawal from caffeine typically occurs within 12 to 24 hours and peaks one to two days after stopping, with a duration between two and nine days.