Fibromyalgia is considered to be a sensitization problem with the central nervous system, caused by our neurochemicals being out of balance.

This means the brain increases our pain response and doesn’t switch it off when the source of the pain is reduced or disappears.

Some people are more likely to develop fibromyalgia than others - there is likely a genetic component that predisposes us to develop it.

Until recently, before the brain-nerve response to pain and our unbalanced neurochemicals were discovered, several other illnesses were thought to be secondary symptoms of fibromyalgia, because they were commonly seen together.

Fibromyalgia is often co-morbid

These other illnesses are co-morbid - they co-exist with fibromyalgia. To make diagnosis more difficult, the symptoms of these illnesses overlap significantly.

Many people have the other illness first, especially when it causes chronic pain. When the brain is sensitized by the chronic pain, fibromyalgia can develop.

People with fibromyalgia are 2-7 times more likely to have at least one co-morbid illness from the list below.

Irritable bowel syndrome and fibromyalgia

Bowel pain, alternating constipation and diarrhea are the defining features of IBS. These are clearly not symptoms of fibromyalgia, and doctors can easily tell these diseases apart.

Up to 60% of IBS sufferers have fibromyalgia as well, probably because the chronic pain of IBS triggers the development of fibromyalgia.

Rheumatism and fibromyalgia

Rheumatic diseases, including rheumatoid arthritis, polymyalgia rheumatica, lupus and others, almost always have inflammation, and inflammation is not a symptom of fibromyalgia.

Because these diseases cause chronic pain and disturb sleep (causing an imbalance in neurochemicals), people who are genetically predisposed to developing fibromyalgia, will develop it alongside their rheumatic disease.

Up to 30% of rheumatism patients have fibromyalgia as well.

Corticosteriod medications typically improve rheumatic illnesses, bringing the generalised inflammation under control, but they do not reduce fibromyalgia symptoms.


Costochondritis can develop after an injury or viral chest infection and can stick around for a long time. It’s an inflammatory condition, that causes pain when pressing on the sternum and around the ribs.  Costochondritis is sometimes found together with fibromyalgia, but it is not yet well understood.

Restless leg syndrome

There is a significant overlap in restless leg syndrome sufferers and fibromyalgia, but the link is not well understood yet.

Myofascial pain syndrome and fibromyalgia

Myofascial pain syndrome and fibromyalgia are so similar that doctors can rarely differentiate. Plus they commonly occur together.

  • Fibromyalgia causes widespread areas of pain, with many tender points, which change location over time.
  • Myofascial pain syndrome is caused by trigger points in individual muscles, and these don't change location.

Trigger points are found with tight sections of a muscle, but tender points are found also outside these taut sections. You can generally feel the difference between the lumpiness of a trigger point (with referred pain), and the smoothness of a tender point (where pain is only at the tender point).

Some doctors believe that myofascial pain syndrome is a focal form of fibromyalgia.

Depression and fibromyalgia

If you are in pain all the time, you are likely to develop depression and anxiety. Other illnesses that cause chronic pain also commonly cause depression. Fibromyalgia sufferers have the added bonus of our neurochemicals being unbalanced - those same neurochemicals control our moods.

Trauma survivors who develop PTSD are also very likely to develop fibromyalgia.

Up to 70% of fibromyalgia sufferers are reported to have some form of major depression or anxiety during their life.

Insomnia and fibromyalgia

When you are sick or in pain, you typically don’t sleep well.  Fibromyalgia’s unbalanced neurochemicals make that worse - these neurochemicals control our sleep-wake cycles.

A bad night of sleep results in even more unbalanced neurochemicals, and a stronger sensitization of the pain response.

That’s why it’s most important for us to do everything possible to get enough quality sleep. Lack of quality sleep is the top culprit that makes fibromyalgia pain worse for me.

Migraines and chronic headache and fibromyalgia

The same neurochemicals that are out of balance in fibromyalgia patients can cause chronic headaches and migraines, so there is no real surprise that these illnesses often co-exist.

Unfortunately, there is not much research into patients that suffer both migraines and fibromyalgia.

Prolonged viral infections

I have ongoing troubles with this - sinus infections, sore throats, light and temperature sensitivities, light fever, enlarged lymph nodes. When blood tests and sinus exams could not find anything, these were put down to being a symptom of fibromyalgia.

But current understanding suggests they are a separate problem, which may be related to chronic fatigue syndrome.

Chronic fatigue syndrome (CFS) / myalgic encephalitis (ME)

The defining feature of CFS is the ongoing exhaustion, not usually a symptom of fibromyalgia alone. All the other symptoms overlap - generalized pain, headaches and sleep problems. CFS/ME is typically triggered by a long flu-like viral infection.

Up to 70% of CFS sufferers may also have fibromyalgia - they meet the current criteria for diagnosis.

Tempero-mandibular disorders (TMJ)

People in pain commonly clench their teeth together, and can easily develop bruxism (teeth grinding) and TMJ problems. This can often lead to headaches and earaches.

This is perhaps a secondary problem to fibromyalgia or another chronic pain illness, as it is generally a response to chronic pain.

Co-morbidity is a perfect area to research

When so many illnesses are co-morbid with fibromyalgia, it suggests there is an underlying problem. Perhaps it is the unbalanced neurochemicals, a genetic component, central sensitization, or another physical problem.

Developing treatments that target these underlying problems will lead to better understanding of all of these diseases.

What illnesses are co-morbid with your fibromyalgia?

I’ve collected IBS, costochondritis, migraines/headaches, endometriosis, TMJ, PTSD, insomnia, I had CFS in the past, and am currently being investigated for rheumatism, another viral infection and interstitial cystitis. So many other illnesses with fibromyalgia to deal with.

What illnesses co-exist with your fibromyalgia?