A chronic pain disorder with a multitude of symptoms, fibromyalgia (FM) affects more 3 million Americans. Although 80 to 90 percent of those affected are women, men and children get fibromylagia, too. The cause of FM isn’t known, but many researchers believe that FM is the result of abnormal pain processing resulting from “central sensitization.”

The theory is that chronic pain actually changes the sensitivity of the brain to pain, making people feel pain from stimuli that wouldn’t normally be painful. FM patients also seem to have changes in nerve signaling chemicals and nervous system related hormones.

A number of scientific studies have shown that FM patients have abnormal blood flow to the thalamus region of the brain, abnormalities in the hypothalamic-pituitary-adrenal axis (the “fight or flight” system), low levels of serotonin and tryptophan, and abnormalities in immune system signaling. Recent studies also show that some people may have a genetic predisposition to FM.

For the latest information about FM, visit the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) website.

Learn more about common overlapping conditions. Also contact other not-for-profit health organizations for more information about these related conditions.

Revised January 8, 2009