Researchers Say Chronic Pain Patients Don't Process Body's Natural Pain Relievers
By Salynn Boyles
WebMD Medical News Reviewed By Louise Chang, MD
on Thursday, November 30, 2006

Nov. 30, 2006 -- There is now "overwhelming" scientific evidence showing that fibromyalgia and related chronic pain conditions are real, but their clinical management leaves much to be desired.
That is the conclusion of two researchers from the University of Michigan who have studied fibromyalgia for several years.
Because there has been no obvious physiological cause for the pain disorder, doctors still routinely dismiss fibromyalgia as being "in a patient's head."
But after reviewing the research, Richard E. Harris, PhD, and Daniel J. Clauw, MD, write that it is increasingly clear that fibromyalgia is a central nervous system disorder and that patients experience hypersensitivity to pain. There also appears to be a fairly strong genetic component to 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," Harris and Clauw write in the December issue of the journal Current Pain and Headache Reports.
Brain Imaging Studies
As many as 10 million Americans may have fibromyalgia, according to The National Fibromyalgia Association.
The disorder is characterized by chronic pain throughout the body, but symptoms may also include fatiguefatigue, headaches, and problems with memory and concentration.
Brain imaging studies conducted at the University of Michigan and other research centers in recent years show clear differences in responses to pain stimulation among people with and without fibromyalgia.
Compared to people without the disorder, fibromyalgia patients showed increased brain activity in response to pain.
"These studies indicate that fibromyalgia patients have abnormalities within their central brain structures," Clauw says.
Research by Harris, Clauw, and colleagues also suggests that fibromyalgia patients don't process the body's natural pain relievers as efficiently as people without the disorder.
"We think that these may have both a heightened sensitivity to pain and this dysfunction in their analgesic [painkilling] mechanism," Harris tells WebMD. "It is not yet clear how this all fits together."
National Fibromyalgia Association president and founder Lynne Matallana tells WebMD that the doctors who treat fibromyalgia patients face a unique challenge.
"This is a new paradigm for medical professionals to understand," she says. "It isn't a virus, or bacteria or inflammation. It isn't a tumor or something else that you can see. It is a problem within the pain-processing center of the central nervous system."
Treatment Options Still Few
While the recent research has done much to improve the understanding of fibromyalgia and related chronic pain conditions, few advances have been made in the treatment of these disorders, Harris says.
The use of medications such as antidepressants can help some patients with fibromyalgia. And regular exercise seems to help many patients.
Acupuncture has been shown to reduce pain in some studies, but not others, he adds.
Matallana says several drug companies are in the later stages of testing several new drugs designed specifically for the treatment of fibromyalgia, which target the central nervous system.
"We are really excited about this research," she says.
SOURCES: Harris, R. and Clauw, D. Current Pain and Headache Reports, December 2006; online edition. Richard E. Harris, PhD, research investigator, University of Michigan Medical Center, Ann Arbor. Daniel J. Clauw, MD, department of medicine, division of rheumatology, University of Michigan Medical Center, Ann Arbor. Lynne Matallana, president and founder, National Fibromyalgia Association.