Pain From Fibromyalgia Is Real, Researchers Say

Fibromyalgia often has been misdiagnosed as arthritis or even a psychological issue. Increasingly, though, the scientific knowledge about fibromyalgia is growing, and a new paper from the University of Michigan Health System says there are "overwhelming data" that the condition is real, is characterized by a lower pain threshold and is associated with genetic factors that can make some people more likely to develop fibromyalgia.

The review paper, in the December issue of the journal Current Pain and Headache Reports, cites recent studies involving pain, genetics, brain activity and more. The paper's authors hope these findings will lead to a better understanding and acceptance of fibromyalgia and related conditions.

"It is time for us to move past the rhetoric about whether these conditions are real, and take these patients seriously as we endeavor to learn more about the causes and most effective treatments for these disorders," says Richard E. Harris, Ph.D., research investigator in the Division of Rheumatology at the U-M Medical School's Department of Internal Medicine and a researcher at the U-M Health System's Chronic Pain and Fatigue Research Center.

A growing amount of research related to the neurobiology of the condition supports the notion that the pain of fibromyalgia is real. Studies at U-M and elsewhere using two neuroimaging techniques -- functional magnetic resonance imaging (fMRI) and single photon emission computed tomography (SPECT) -- indicate there is a difference between patients with and without fibromyalgia.

"In people without pain, these structures encode pain sensations normally. In people with fibromyalgia, the neural activity increased," says Daniel J. Clauw, M.D., director of the U-M Chronic Pain and Fatigue Research Center and professor of rheumatology at the U-M Medical School, and an author of the new paper. "These studies indicate that fibromyalgia patients have abnormalities within their central brain structures."

In a 2003 paper in the journal Science, a U-M team reported that a small variation in the gene that encodes the enzyme called catechol-O-methyl transferase, or COMT, made a significant difference in the pain tolerance, and pain-related emotions and feelings, of healthy volunteers. Researchers also have found that individual mutations in the COMT gene are related to the future development of temporomandibular joint disorder, also known as TMD or TMJ, a condition related to fibromyalgia.

Together, these studies about COMT and numerous studies with animals suggest that pain sensitivity is determined at least in part by a person's genetic makeup, Clauw says.

The authors note that there are some legitimate areas of debate regarding fibromyalgia, including disagreements about how precisely it should be defined and whether people with the condition deserve compensation. But none of those disagreements should detract from the acceptance of it as a condition causing real pain, they say.

Reference: Current Pain and Headache Reports, Dec. 2006, pp. 403-7.