What is fibromyalgia?
Key takeaways
Fibromyalgia is a problem in how the nervous system processes pain, not damage to the muscles or joints. The system amplifies ordinary signals into pain.
Fibromyalgia is diagnosed when widespread pain has lasted three months or more. Fatigue and difficulty thinking clearly nearly always come too, but pain is the central feature.
There is often a trigger behind fibromyalgia’s onset, an injury, an infection, or sustained stress, though for some people it appears with no clear cause.
Fibromyalgia and ME/CFS overlap, but they are not the same condition: fibromyalgia centres on widespread pain, while ME/CFS centres on post-exertional malaise. Treating them as one leads to management that fits the wrong illness.
If you or someone you love has just received a fibromyalgia diagnosis, you probably have a lot of questions. Many people reach this point after years of being dismissed or misdiagnosed. This page is a gentle starting point.
Fibromyalgia is a long-term condition that causes widespread pain, fatigue, and cognitive difficulties. It does not show up on scans or blood tests, which is often why it takes so long to diagnose. It is a real, well-established medical condition.
It is not a disease of damaged tissue
For years, fibromyalgia was assumed to be a problem with the muscles or joints themselves. The word ‘fibromyalgia’ literally means ‘pain in the fibrous tissues’.
That understanding has changed. Research suggests fibromyalgia is a condition of the central nervous system, specifically how the brain and spinal cord process pain signals.
Think of a sound system with the volume turned up too high. The signals coming in are no greater than normal: a light touch, a bit of pressure, a change in temperature. But the output is amplified to the point of distortion. In fibromyalgia, the nervous system behaves something like this. Ordinary sensations can register as painful, and real pain can feel overwhelming.
The defining feature of fibromyalgia is widespread pain: pain in multiple areas of the body, lasting three months or more. Fatigue and cognitive difficulties almost always come with it, but pain is what sets fibromyalgia apart from other chronic illnesses.
How does it start?
Fibromyalgia often develops after a specific event, though it can also appear without any clear trigger.
- Physical trauma. A significant injury, a car accident, or major surgery can sometimes trigger fibromyalgia, particularly when recovery is prolonged.
- Infection. Viral or bacterial infections are a recognised trigger. Some people develop fibromyalgia after an illness that they otherwise recover from.
- Prolonged stress. Extended periods of severe physical or emotional stress, including trauma, bereavement, or sustained overwork, can act as a trigger. This is particularly true in people who may already be predisposed.
- No clear trigger at all. In some cases fibromyalgia develops gradually, with no identifiable starting point.
Research suggests some people are genetically predisposed to fibromyalgia. Having a close relative with the condition increases the likelihood of developing it, though it is not a simple inherited disease.
Who gets it?
Fibromyalgia can affect anyone. It is found in every country and every demographic.
That said, some patterns are consistent:
It is more commonly diagnosed in women than in men, by a significant margin. Some researchers argue this reflects a genuine biological difference. Others suggest it partly reflects diagnostic bias, with men underdiagnosed when they present with similar symptoms.
It is most often diagnosed between the ages of 30 and 50, but it can affect children, teenagers, and older adults.
It frequently coexists with other conditions, including ME/CFS, irritable bowel syndrome, migraine, and chronic pelvic pain.
Is it the same as ME/CFS?
Not quite, but the two overlap significantly, and some people meet the diagnostic criteria for both.
Both conditions involve fatigue, unrefreshing sleep, and cognitive difficulties. The distinguishing feature is what sits at the centre of the illness. In fibromyalgia, that is widespread pain. In ME/CFS, it is post-exertional malaise (PEM): a significant worsening of symptoms after physical or mental effort, often delayed by hours or days.
People with fibromyalgia also experience flares, periods where symptoms worsen, but these are not the same as the delayed-crash pattern that defines PEM. Treating the two as interchangeable is a common mistake, and it can lead to management strategies that work well for one condition but not the other.
For more on ME/CFS, see our ME/CFS hub.
Where to go next
If you are newly diagnosed, these pages cover what comes next in more depth.
Fibromyalgia symptoms: the main symptoms explained in plain language.
Causes and triggers: what causes fibromyalgia to develop, and what triggers day-to-day flares.
Managing fibromyalgia: pain, sleep, gentle movement, and pacing.
Living with fibromyalgia: practical strategies for adapting chores, your home environment, and boundaries.
Overlapping conditions: the conditions that commonly co-occur with fibromyalgia, and why.