As of now, no one knows exactly what sets off the constellation of symptoms we know as fibromyalgia. It's quite possible that there are multiple triggers. It's also possible that the cause is different for different people, just as the symptoms are. But there is certainly no shortage of theories as to what the culprit might be.

Central Nervous System Defect

The pain associated with fibromyalgia is most likely the result of an abnormality in your central nervous system (CNS), which is made up of your brain and spine. The CNS processes and coordinates the nerve signals it receives from the peripheral nervous system, including those that alert you to pain. Pain is a normal reaction to a potentially harmful external stimulus and acts as your body's internal alarm system.

In people who have fibro, there appears to be a defect in the CNS sensory processing that alerts us to pain. For starters, fibro patients tend to have more nerves involved in transmitting pain. In addition, the internal “computers” that process pain are overactive. As a result, pain signals are intensified. The supercharged signals in turn create more nerve connections in your spine that perpetuate the cycle of pain.

Physical Trauma or Injury

Many experts believe that the pain and fatigue of fibromyalgia may result from certain types of physical trauma. Neck injuries, in particular, seem to bring on the symptoms of fibro. So if someone is genetically predisposed to getting fibromyalgia, as experts suspect, an accident or injury could be the environmental trigger that sets off the condition.

Illness or Infection

In some people, the onset of fibromyalgia is preceded by an illness, raising the prospect that FMS is brought on by infection. Possible culprits include Lyme disease, hepatitis, and the Epstein-Barr virus, which causes mononucleosis. Illness or infection as a cause, however, fails to explain the cases that seem to appear from out of nowhere with no prior illness.

Emotional Stress

Many people with fibromyalgia note that they were going through periods of severe emotional stress around the time their symptoms started. Divorce, the death of a loved one, or professional/financial hardships all can increase the risk of developing fibromyalgia. It is rare, however, for FMS to develop without other factors also being present.

Hormonal and Chemical Disturbances

Some experts believe that fibromyalgia is precipitated by hormonal changes and chemical disturbances. Hormones are chemicals in the body that regulate specific activities of different organs. Among the hormones that are altered or affected in people with fibro are those described in the following sections.

Substance P

Substance P is a chemical that increases your nerves' sensitivity to pain. In people with FMS, the amount of substance P found in spinal fluid is three times the normal amount of that in healthy people.

Serotonin

Serotonin is a neurotransmitter involved in regulating pain and mood. It also facilitates sound sleep. In people with fibromyalgia, serotonin levels are commonly lower than normal.

HPA Axis Hormones

The hypothalamic-pituitary-adrenal (HPA) axis is responsible for the release of hormones that help you cope with stress. In people who have fibro, there may be an imbalance of hormones in the HPA axis, which hinders the body's fight-or-flight response and renders it less effective.

Growth Hormones

Growth hormones are secreted during the deepest stages of sleep and play a role in helping the body rebuild itself. People who have FMS generally have lower levels of growth hormones. Some studies have shown that correcting these levels by giving patients growth hormone may significantly reduce FMS symptoms.

Sleep Disturbance

It's hard to say whether sleep difficulties cause fibromyalgia, result from it, or both. But some people believe that sleep difficulties are at the root of this condition. Studies have found that even healthy people who had fragmented stage 4 sleep, the deepest stage of sleep, were susceptible to the aches and pains seen in fibromyalgia. It is during this critical stage of sleep that our bodies restore themselves and secrete important immune-boosting substances and growth hormone.