Chronic Fatigue Syndrome - Description

Chronic fatigue syndrome is known by many different names. These names include chronic fatigue and immune disorder (CFIDS), myalgic encephalomyelitis (pronounced my-AL-jik en-SEF-uh-lo-MY-uh-LY-tiss), low natural killer cell disease, post-viral syndrome, Epstein-Barr disease, and Yuppie flu. Such names suggest a number of possible causes for CFS. Researchers have not been able to find out which of these causes, or which combination of factors, is responsible for the disease.

Reports of a CFS-like disease date back to 1869. People with the disease were said to have neurasthenia ("nerve weakness," pronounced noor-ess-THEE-nee-uh) or fibromyalgia ("muscle pain," pronounced FI-bro-my-AL-ja). These disorders are now thought to be related to chronic fatigue syndrome.

Another clue to the cause of CFS appeared in the mid-1980s when doctors found antibodies to the Epstein-Barr virus (EBV) in the blood of many people with CFS. Antibodies are produced by the body when it needs to fight off an infection. Some doctors believed that these antibodies meant that chronic fatigue syndrome was caused by the Epstein-Barr virus. It was soon discovered, however, that many people who did not have CFS also had EBV antibodies in their blood. Some scientists now think that EBV may contribute to CFS, but it is not the only factor.

The term Yuppie flu became popular because so many young, middle-class people developed the disease. More detailed studies showed that people of every age, gender, race, and income group can get CFS. The group most at risk for the disease, however, is women aged 25 to 45 years.

Estimating the number of people with CFS is difficult because its symptoms are so similar to those of other diseases. The U.S. Centers for Disease Control and Prevention (CDC) now believe that 4 to 10 out of every 100,000 Americans have CFS. The CFIDS Foundation estimates that about 500,000 adults (0.3 percent of the population) have CFS. These estimates do not include children.