It's not clear why some people develop fibromyalgia. The exact cause is unknown, but it's likely that a number of factors are involved.
Here are some of the main factors thought to contribute to the condition.
One of the main theories is that people with fibromyalgia have developed changes in the way the central nervous system processes the pain messages carried around the body.
This could be the result of changes to chemicals in the nervous system.
The central nervous system (brain, spinal cord and nerves) transmits information all over your body through a network of specialised cells.
Changes in the way this system works may explain why fibromyalgia results in constant feelings of, and extreme sensitivity to, pain.
Research has found people with fibromyalgia have abnormally low levels of the hormones serotonin, noradrenaline and dopamine in their brains.
Low levels of these hormones may be a key factor in the cause of fibromyalgia, as they're important in regulating things like:
- your response to stressful situations
These hormones also play a role in processing pain messages sent by the nerves. Increasing the hormone levels with medication can disrupt these signals.
Some researchers have also suggested that changes in the levels of some other hormones, such as cortisol, which is released when the body is under stress, may contribute to fibromyalgia.
It's possible that disturbed sleep patterns may be a cause of fibromyalgia, rather than just a symptom.
Fibromyalgia can prevent you sleeping deeply and cause extreme tiredness (fatigue).
People with the condition who sleep badly can also have higher levels of pain, suggesting that these sleep problems contribute to the other symptoms of fibromyalgia.
Research has suggested genetics may play a small part in the development of fibromyalgia, with some people perhaps more likely than others to develop the condition because of their genes.
If this is the case, genetics could explain why many people develop fibromyalgia after some sort of trigger.
Fibromyalgia is often triggered by a stressful event, including physical stress or emotional (psychological) stress.
Possible triggers for the condition include:
- an injury
- a viral infection
- giving birth
- having an operation
- the breakdown of a relationship
- being in an abusive relationship
- the death of a loved one
But in some cases fibromyalgia does not develop after any obvious trigger.
There are several other conditions often associated with fibromyalgia.
Generally, these are rheumatic conditions (affecting the joints, muscles and bones), such as:
- osteoarthritis – when damage to the joints causes pain and stiffness
- lupus – when the immune system mistakenly attacks healthy cells and tissues in various parts of the body
- rheumatoid arthritis – when the immune system mistakenly attacks healthy cells in the joints, causing pain and swelling
- ankylosing spondylitis – pain and swelling in parts of the spine
- temporomandibular disorder (TMD) – a condition that can cause pain in the jaw, cheeks, ears and temples
Conditions like these are usually tested for when diagnosing fibromyalgia.