Clinical examinations often revealed no concrete physiological findings. X-rays, blood tests, and muscle biopsies appeared normal, and therefore the symptoms seemed unexplainable. The patient was frequently told the symptoms were "all in their head".
Psychological stresses have long been regarded as contributory to fibromyalgia syndrome, but now much new research is ongoing. Better physiological and biological evidence is being gathered.
Sleep Abnormalities and Fibromyalgia
In 1975, two Canadian physicians and researchers, Harvey Moldofsky, MD, and Hugh Smythe, MD, were asked by colleagues at the University of Toronto to interview patients complaining of chronic muscle pain for which no physiological cause could be found. Following the interviews the two Canadian researchers suspected sleep abnormality and further studied the patients using EEG (brain wave test). The device measured the patients brain waves during sleep and it was found that the patients had a deficiency in the deepest stage of sleep, known as stage 4.
The researchers continued studying sleep disorder as a factor in fibromyalgia. One of their studies involved awakening healthy people and disrupting their sleep pattern as they entered stage 4 of sleep. Interestingly, it was found that the healthy subjects developed fibromyalgia symptoms when their sleep was disturbed, but the symptoms subsided when they were permitted to sleep undisturbed.
As the two researchers analyzed the study results, they concluded that the patients not only had sleep abnormalities but also had disregulation of normal body circadian rhythms affecting periods of wakefulness too.
Muscle Abnormalities and Fibromyalgia
Until about thirty years ago, fibrositis was the term used rather than fibromyalgia. Fibrositis was an incorrect term because it means muscle inflammation, and it is now known that inflammation does not exist in the muscles of fibromyalgia patients. In the early 1980's some researchers described varied muscle biopsy abnormalities in people with fibromyalgia but by 1989 a controlled, blinded study was done which revealed an opposite conclusion that there were no more muscle abnormalities in fibromyalgia patients than in pain-free control subjects.
In 1986, a team of researchers from Sweden theorized that the muscle pain of fibromyalgia is a result of tissue hypoxia because of the inability of the muscles to functionally use oxygen. It is thought to this day that this applies to some patients.
Robert Bennett, MD, from Oregon, along with other researchers have analyzed the connection between sleep disorders and muscle damage. Growth hormone which is important in muscle maintenance and repair, is secreted during sleep stage 4. The research of Dr. Bennett indicates that about one-third of fibromyalgia patients have a growth hormone deficiency.
Substance P and Serotonin
There has been some research which has focused on the chemicals of the nervous system which help regulate pain messages sent out to brains. Two such chemicals are:
- Substance P
According to A.D.A.M, "Substance P is a neurotransmitter associated with increased pain perception." Normally, substance P begins the pain signal process which follows painful tissue injury.
According to A.D.A.M, "Serotonin is synthesized from the amino acid tryptophan by enterochromaffin cells in the stomach and bronchi (lungs)." Serotonin normally reduces the intensity of pain signals. Serotonin has also been found to play an important role in sleep regulation. There are studies which show abnormal levels of both of these hormones in people with fibromyalgia.
Research also has described some people with fibromyalgia as having decreased blood flow to certain areas of the brain which help modulate pain signals sent from the spinal cord to the brain. The theory that some people with fibromyalgia have exceptionally high intensity pain messages sent to the brain, along with a deficiency in pain inhibition, is supported by the research indicating abnormal levels of substance P and serotonin, and decreased brain blood flow.