later spreading into other body regions (mid-back, arms, spine, lower back and thighs). Although people who suffer from the disorder claim that they permanently feel some degree of pain in the muscles and joints, the symptoms generated by fibromyalgia are usually episodic, occurring in "flares".

Apart from pain and fatigue, people affected by fibromyalgia may also experience physical weakness, increased nervous excitability, migraines, short-term memory loss, poor concentration, anxiety, depression and confusion. The problem with the symptoms of fibromyalgia is that they can't usually be revealed by medical examinations. In the absence of any physical traces, most physicians are tempted to label people with fibromyalgia as "hypochondriacs", disregarding the neurological nature of the disorder. However, various experiments conducted in the past have found similarities in all people with fibromyalgia, and elaborate medical examinations can reveal neurological dysfunctions in people affected by the disorder.

Fibromyalgia is a complex phenomenon and medical scientists believe that there are multiple factors responsible for causing it. Studies in the field have suggested that people with the disorder perceive external stimuli at abnormally high intensities, as a consequence of neurological dysfunctions. Recently conducted experiments have revealed that some of the people with fibromyalgia show clear signs of allodynia (hyperactive brain response to otherwise normal stimuli), while others show clear signs of hyperalgesia (abnormally high sensitivity to pain stimuli). These findings are very important in revealing the actual causes of fibromyalgia and they have also proved that the disorder has a clear medical basis.

Sleep disorders are also suspected to be causes of fibromyalgia. Statistics indicate that more than 95 percent of people with fibromyalgia suffer from sleep apnea or insomnia. Until recently, scientists believed that sleep disorders were the consequence of fibromyalgia but it now turns out to be the other way around. The majority of people affected by fibromyalgia recall having trouble sleeping long before they have first experienced muscular pain and weakness. Hence, medical scientists believe that fibromyalgia occurs on the premises of inappropriate sleeping patterns, and they state that anyone with sleeping problems is very exposed to developing neurological disorders.

Scientists explain that certain neurotransmitters such as serotonin (a substance that regulates the intensity of pain signals sent to the brain), are produced during sleep and people with fibromyalgia have a deficit of these hormones due to sleep abnormalities. Thus, the treatment for fibromyalgia should be firstly aimed at overcoming patients' sleeping problems.

Another cause of fibromyalgia appears to be poor muscle oxygenation. Medical scientists claim that inappropriate oxygenation of the muscles is a plausible explanation for symptoms such as muscular weakness and stiffness, similar to the manifestations of rheumatoid arthritis. Although medical scientists haven't yet unveiled the factors that prevent the oxygenation of the muscles, future research might provide medicine with an answer to the puzzle.