is
unknown. Physical or emotional trauma may play a role in development of the syndrome. A
number of lines of evidence suggest that fibromyalgia patients have abnormal pain
transmission responses.
It has been suggested that sleep disturbances, which are common in fibromyalgia
patients, may actually cause the condition. Another hypothesis suggests that the disorder
may be associated with changes in skeletal muscle metabolism, possibly caused by decreased
blood flow, which could cause chronic fatigue and weakness.
Others have suggested that an infectious microbe, such as a virus, triggers the
illness. At this point, no such virus or microbe has been identified.
Pilot studies have shown a possible inherited tendency toward the disease, though
evidence is very preliminary.
The disorder has an increased frequency among women 20 to 50 years old. The prevalence
of the disease has been estimated between 0.7% and 13% for women, and between 0.2% and
3.9% for men.
