The Irritable Bowel Syndrome-Fibromyalgia Connection

There Is A Connection Between These Two Functional Disorders

Woman With Head In Hands
IBS and fibromyalgia can occur together, complicating both conditions. Image © David De Lossy / DigitalVision / Getty Images

As many as one-third of irritable bowel syndrome (IBS) patients have described extra intestinal symptoms such as rashes, tension headaches, and muscle pains. It's estimated that more than half of IBS patients also have fibromyalgia syndrome (FMS). Conversely, as many as 70% of FMS patients have reported experiencing symptoms of IBS. Could there be a common cause for both conditions?


FMS is a disorder of the musculoskeletal system that is associated with symptoms of general muscle aches, stiffness, overall fatigue, and poor sleeping habits (see Fibromyalgia Symptoms Checklist for a complete list of fibromyalgia symptoms).

Symptoms can vary in both severity and duration; the pain may be dull or knife-like, linger persistently, or be intermittent. Like IBS, FMS is a functional disorder, and therefore tests to find the origins of the pain often come back negative (see below for the diagnostic criteria for FMS). Approximately 3.4% of women, and 5% of men suffer from FMS.

The IBS-FMS Connection

Given the co-existence of IBS and FM in so many patients, it is reasonable to consider a connection. Even though IBS affects the gastrointestinal tract and FMS the musculoskeletal system, there are similarities that the two conditions share. Neither condition can be explained by organic disease; they are considered functional disorders. Both occur frequently in women and the onset may be during a stressful event in life. Cognitive behavior therapy and certain types of prescription drugs are effective in both.

Research has suggested that people with IBS or FMS respond to pain differently than other persons.

However, IBS patients have an altered response to visceral (intestinal) pain, while persons with FMS have an altered response to somatic (skin and muscle) pain. Not surprisingly, further studies have shown that people with both conditions have an altered response to both types of pain. Additionally, persons with severe IBS were more likely to have FMS than those with less acute symptoms.

Although researchers suggest a common mechanism for both disorders, its origins are still unknown. Relatively speaking, the medical community has only just recognized IBS and FMS as legitimate disorders and not psychosomatic problems. Therefore, research on either condition is still in its infancy, and studies connecting the two are rare. However, there is hope, as researchers are taking new interest in discovering why IBS and FMS seem to be connected.

Diagnosing Fibromyalgia

In 1990, the first criteria for the diagnosis of fibromyalgia were established by the American College of Rheumatology. The criteria were then revised in 2010. These are:


A patient satisfies diagnostic criteria for fibromyalgia if the following 3 conditions are met:

  1. Widespread pain index (WPI) ≥7 and symptom severity (SS) scale score ≥ 5 or WPI 3–6 and SS scale score ≥9.
  2. Symptoms have been present at a similar level for at least 3 months.
  3. The patient does not have a disorder that would otherwise explain the pain.


  1. WPI: note the number areas in which the patient has had pain over the last week. In how many areas has the patient had pain? Score will be between 0 and 19.
    • Shoulder girdle, left
    • Shoulder girdle, right
    • Upper arm, left
    • Upper arm, right
    • Lower arm, left
    • Lower arm, right
    • Hip (buttock, trochanter), left
    • Hip (buttock, trochanter), right
    • Upper leg, left
    • Upper leg, right
    • Lower leg, left
    • Lower leg, right
    • Jaw, left
    • Jaw, right
    • Chest
    • Abdomen
    • Upper back
    • Lower back
    • Neck
  1. SS scale score:
    • Fatigue
    • Waking unrefreshed
    • Cognitive symptoms
      • For the each of the 3 symptoms above, indicate the level of severity over the past week using the following scale:
      • 0 = no problem
      • 1 = slight or mild problems, generally mild or intermittent
      • 2 = moderate, considerable problems, often present and/or at a moderate level
      • 3 = severe: pervasive, continuous, life-disturbing problems
    • Considering somatic symptoms in general, indicate whether the patient has:*
      • 0 = no symptoms
      • 1 = few symptoms
      • 2 = a moderate number of symptoms
      • 3 = a great deal of symptoms

The SS scale score is the sum of the severity of the 3 symptoms (fatigue, waking unrefreshed, cognitive symptoms) plus the extent (severity) of somatic symptoms in general.

The final score is between 0 and 12.

* Somatic symptoms that might be considered: muscle pain, irritable bowel syndrome, fatigue/tiredness, thinking or remembering problem, muscle weakness, headache, pain/cramps in the abdomen, numbness/tingling, dizziness, insomnia, depression, constipation, pain in the upper abdomen, nausea, nervousness, chest pain, blurred vision, fever, diarrhea, dry mouth, itching, wheezing, Raynaud's phenomenon, hives/welts, ringing in ears, vomiting, heartburn, oral ulcers, loss of/change in taste, seizures, dry eyes, shortness of breath, loss of appetite, rash, sun sensitivity, hearing difficulties, easy bruising, hair loss, frequent urination, painful urination, and bladder spasms.


Veale D, Kavanagh G, Fielding JF, Fitzgerald O. "Primary fibromyalgia and the irritable bowel syndrome." Br J Rheumatol. 1991;30:220-222.

Lubrano E, Iovino P, Tremolaterra F, et al. "Fibromyalgia in patients with irritable bowel syndrome. An association with the severity of the intestinal disorder." Int J Colorectal Dis. 2001;16:211-215.

Wolfe F, Clauw DJ, Fitzcharles MA, et al. "The American College of Rheumatology preliminary diagnostic criteria for fibromyalgia and measurement of symptom severity." Arthritis Care Res (Hoboken). 2010 May;62(5):600-610.

Wolfe F, Smythe HA, Yunus MB, et al. "The American College of Rheumatology 1990 Criteria for the Classification of Fibromyalgia. Report of the Multicenter Criteria Committee." Arthritis Rheum. 1990;33:160-172.

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