I'm Gwen Outen with the VOA Special English Health Report.

Coffee, tea and soft drinks usually contain caffeine. Caffeine is also found in chocolate, in medicine for colds and in drugs that keep people awake.

In the United States, adults who use products with caffeine get an average of about two hundred eighty milligrams a day. This equals the caffeine in about two large cups of coffee. A report this month in the Journal of the American Dietetic Association says adults drink nearly half the coffee they did fifty years ago. But they still get most of their caffeine from coffee.

In general, the more people drink, the more severe the effects if they miss a day. Yet a recent report says people who drink as little as one cup of coffee a day can become dependent on caffeine. In fact, it says caffeine withdrawal should be listed as a mental disorder.

Researchers examined more than sixty studies on caffeine withdrawal from the last one hundred seventy years. They identified several common effects, such as headaches and sleepiness. Some people have difficulty thinking. Others get angry easily or become very sad.

The researchers found that half the people suffered headaches if they did not have caffeine. Thirteen percent had a more serious problem. They were unable to work or do other normal activities. These problems generally resulted twelve to twenty-four hours after stopping caffeine.

Ronald Griffiths of Johns Hopkins University in Baltimore, Maryland, led the study. He noted that caffeine is the most commonly used stimulant in the world. A stimulant produces a temporary increase in energy.

The good news is that people can free themselves of caffeine dependence. The researchers say people should slowly reduce the amount of caffeine in their diet. The report appeared in the journal Psychopharmacology.

The report published by the dietetic association is based on a national continuing study of what Americans eat. Researchers from the University of Vermont and the University of Maryland say almost ninety percent of adults have caffeine in their diet. So do seventy-six percent of children, mostly from soft drinks.

After coffee, tea used to provide the second most caffeine for men age eighteen to fifty-four and women eighteen to thirty-four. But tea is now third behind soft drinks.

This VOA Special English Health Report was written by Jerilyn Watson. I'm Gwen Outen.