The exact cause of fibromyalgia is unknown. Research into people with fibromyalgia has identified a number of changes in the way their body functions. However, what causes these changes, and how these cause fibromyalgia, is still not clear.
Changes noticed in people with fibromyalgia include:
- disturbed pain messages
- low levels of hormones
- sleep problems
These are explained in more detail below.
Disturbed pain messages
One of the most likely causes of fibromyalgia is a problem with the way pain messages are carried and received in your body.
The central nervous system (brain, spinal cord and nerves) transmits information all over your body through a network of specialised cells. In people with fibromyalgia, the way pain messages are processed is disturbed. This may explain why fibromyalgia results in constant feelings of pain and extreme sensitivity to pain.
Low levels of hormones
People with fibromyalgia have been found to have lower-than-normal levels of the hormones serotonin, noradrenaline (also known as norepinephrine) and dopamine.
Low levels of these hormones may be a key factor in the cause of fibromyalgia, as they each control many of the processes in the body. For example:
serotonin - helps regulate moods, appetite, and sleep
noradrenaline - this contributes to response in stressful situations
dopamine - this helps to control mood, behaviour and learning.
It is possible that disturbed sleep patterns may be a cause of fibromyalgia, rather than just a symptom. Fibromyalgia can prevent you from sleeping deeply and cause fatigue (extreme tiredness). People with fibromyalgia who sleep badly also seem to feel more pain. This may suggest that the sleep problems in some way contribute to the other symptoms of fibromyalgia.
There may be some risk factors that can either make fibromyalgia more likely, or act as a trigger for the condition. These include:
- physical trauma (damage to the body's tissues)
- psychological trauma (an incident that causes emotional damage, such as the death of a loved one)
- a viral infection (such as hepatitis B, hepatitis C or HIV and AIDS)
- being depressed
There may be a genetic link to fibromyalgia, with some people more likely than others to develop the condition due to their genes (the units of genetic material inherited from their parents). If this is the case, a genetic predisposition (tendency) could explain why some people develop fibromyalgia after some sort of trigger.
There are several other conditions that can lead to fibromyalgia. In these cases, the condition is known as secondary fibromyalgia. Conditions that can cause fibromyalgia include:
- metabolic disturbances such as an underactive thyroid - when the thyroid gland does not produce enough of the thyroid hormone
- inflammatory disorders such as rheumatoid arthritis - a condition that causes joint pain and stiffness
It is also possible there is no single cause of fibromyalgia, and that several of the above factors may combine to cause the condition.