Theories/Speculation

• One widely respected theory as to the cause of fibromyalgia focuses on the idea that some people have a lower threshold of pain than others due to their more heightened sensitivity to pain signals that are transmitted to the brain. The stimulation of pain-signaling nerves in the brain is higher in those that develop fibromyalgia. The pain receptors of these people will also become much more sensitive and wind up overreacting to any pain signal. However, what actually causes any of this is not known. Yet another theory about the cause of fibromyalgia takes into account that many of those that have it have lowered levels of human growth hormone, which may lead to the muscle pain that defines the condition.
  
  

Effects

• Fibromyalgia may be associated with lower levels of a substance called serotonin in the bloodstream. Serotonin is found in the brain and produces a calming effect on the nerves. Another substance, called Substance P, is found in a large number of those with fibromyalgia and it has an opposite effect, making pain signals more pronounced.
  
  

Types

• There are other ideas about the causes of fibromyalgia. Disturbances in an individual's sleep pattern occur during fibromyalgia, but rather than it being a symptom it may actually be one of the factors contributing to it. Injuries to the upper spine seem to have triggered fibromyalgia in a population of people, with the injury working on the central nervous system to produce the symptoms. Infections have also been linked to fibromyalgia and may precipitate the condition in certain people.
  
  

Function

• The autonomic nervous system controls involuntary movements such as heart rate, sweating and the contractions of blood vessels. Somehow these functions become short-circuited in those with fibromyalgia, especially at night, making them tired, sweaty and dizzy. But the exact reason for this is not known. It has also been noted that a decreased blood flow to a person's muscles has been observed in some fibromyalgia patients, which may be part of the problem.
  
  

Identification

• Doctors have a difficult time diagnosing fibromyalgia, as many of its symptoms resemble those of other neurological problems. Your doctor will take into account your gender, age and family history, as fibromyalgia may even be hereditary. The American College of Rheumatology has put down guidelines to diagnose fibromyalgia based on the duration of pain and the number of places on the body that are abnormally tender when mild pressure is applied. However, many doctors feel these guidelines are too strict and that a person can have fibromyalgia despite their symptoms not meeting these requirements.