The exact cause of fibromyalgia syndrome is unknown, however, several factors have been associated with this condition and this has led to several hypotheses and theories relating to the condition and its cause. Some of the possible causes include:-

• In a large majority of patients there is no explainable cause of the condition and it develops on its own.
• Physical trauma for example after road traffic accidents - this may lead to development of long term pain over the muscles and fibrous tissues and development of tender points and other pain conditions associated with fibromyalgia.
• Repetitive injuries at work and strain of particular groups of muscles, tendons and ligaments are also associated with development of fibromyalgia.
• Alterations in pain perception pathways – the most likely cause underlying fibromyalgia is alteration of pain perception by the body or increased sensitivity to pain.

Serotonin is a chemical messenger in the brain. It has been suggested that lower levels of this chemical leads to lower generation of the body’s natural pain relievers or endorphins and as a result the pain threshold may be decreased and pain sensitivity may rise.

Lack of serotonin in the brain also predisposes a person to develop depression and depression is commonly seen in patients with fibromyalgia.
 

• Alterations in hormone levels – levels of growth hormone is found to be lower among patients with fibromyalgia raising speculation that this may be connected to causation of the condition.

In addition several brain chemical messengers called neurotransmitters may be lower than normal. This includes serotonin, noradrenaline and dopamine. While serotonin is associated with moods and sleep, noradrenaline controls the response to a stressful situation. Dopamine on the other hand deals with moods, behaviour, learning, pleasurable sensations and movements.

• Inheritance of faulty genes - some genes have been implicated in fibromyalgia and these have been speculated to be the cause of fibromyalgia running in some families.
• Sleep disturbances are one of the commonest symptoms of fibromyalgia; however, there are studies that show that the causation might be vice versa as well. This means, sleep problems may be the cause of fibromyalgia as well. People with fibromyalgia may have sleep problems that make them feel more pain.
• Psychological trauma has also been associated with fibromyalgia causation.
• Some viral infections such as Hepatitis B, Hepatitis C, HIV/AIDS etc. have been associated with fibromyalgia.
• Depression is a connection with fibromyalgia both as a cause as well as a symptom.
• An underactive thyroid gland may also precipitate fibromyalgia.
• Lupus patients are at an increased risk of developing fibromyalgia syndrome. Up to 30% of lupus patients may eventually go on to be diagnosed with fibromyalgia.
• Certain bone and joint diseases may also predispose a person to develop fibromyalgia. For example, around 10 to 15% of osteoarthritis patients may also develop fibromyalgia. Ankylosing spondylitis and rheumatoid arthritis are other conditions that predispose a person to get fibromyalgia.