IBS and Other Overlapping Health Problems

Common Comorbid Disorders

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Following the old chestnut "when it rains it pours", IBS patients often find themselves dealing with other health problems in addition to their IBS. Medical professionals call these parallel conditions "comorbid disorders." As researchers continue in their quest for better understanding of the underlying causes of IBS, an active area of inquiry focuses on the tendency of IBS patients to experience extra-intestinal symptoms and illnesses at a higher rate than normal.

Here is an overview of what is known so far about IBS and its relationship with other health problems. As you read this, please keep in mind that this tendency toward parallel conditions is not seen in every IBS patient.

Common Comorbid GI Illnesses

Although it is a lousy experience for the patient, it doesn't seem so surprising that an IBS patient would also experience a co-existing gastrointestinal disorder. It may well be that a shared factor is underlying each disorder. Here are some GI illnesses that have been shown to occur at a higher rate in IBS patients than in non-IBS patients (click on each link to get more information):

Common Non-GI Related Comorbid Disorders

More perplexing is the fact that IBS patients are more likely to experience non-gastrointestinal disorders than would normally be expected.

Intuitively, it is harder to grasp why this would be the case. These are some of the disorders that IBS patients experience alongside their IBS:

Comorbid Psychiatric Illnesses

A higher rate of psychiatric illness in IBS patients is a well-established fact. Unfortunately, this information has often been distorted such that IBS patients are told that their digestive problems are all psychological. It is fair to say that there may be underlying factors that contribute to the onset and maintenance of both IBS and any co-existing mental health difficulties. Here are some of the psychiatric disorders that are seen alongside IBS:

Why Is There a Higher Rate of Comorbid Illness?

As of now, there are no clear-cut reasons to explain the phenomenon of comorbid illness and IBS. The puzzle is confounded by the fact that not all IBS patients experience a co-existing disorder. In fact, although overall there is an increased risk of comorbid illness in IBS patients, comorbid illness still affect less than 20% of IBS sufferers.

In some cases, shared explanations could perhaps be identified as the culprit.

This possibility is more likely when the comorbid disorder shares similar features, such as a possible overall problem with digestive motility. Similarly, the link with psychiatric illness could be explained by a shared imbalance of certain neurotransmitters within the central nervous system.

Another possible explanation is that some IBS patients have a tendency to be hyper-aware of physical sensations and symptoms. This excessive attention leads them to be more likely to seek medical advice about their symptoms and thus the greater rates of illness diagnoses. Evidence for this theory comes from the fact that for some disorders there are no shared biological factors that could explain the various illnesses. Like the chicken-and-the-egg, it is unclear whether this hypersensitivity contributes to their IBS, or if experiencing IBS lends one to be more aware of bodily sensations.

Modern science is sure to come up with better answers. One newer area of inquiry is a look at a pathway in the body known as the hypothalamic-pituitary-adrenal axis. This pathway affects many of our bodily systems and appears to be related to how our bodies deal with stress. It has been theorized that a dysfunction in this pathway sets the stage for increased inflammation which contributes to these comorbid problems.

What This Means for You

If you find yourself in the unenviable position of dealing with other health problems in addition to your IBS, talk with your doctor about the possibility of common causal factors. This information may then aid in the development of a shared plan for symptom management. You may find that a whole body approach is more helpful than treatments that target specific symptoms. Options for improving your overall health include improved nutrition, the use of herbal remedies, and engaging in the process of psychotherapy.


Goddard, E., Barth, K., Lydiard, B. Disorders Which Frequently Overlap With Irritable Bowel Syndrome: Can a Shared Neurobiology Explain Their Frequent Association? Primary Psychiatry 2007 :69-7.

Reidl, A., et.al. Somatic comorbidities of irritable bowel syndrome: A systematic analysis Journal of Psychosomatic Research 2008 573-582.

Whitehead, W. et.al. "Comorbidity in Irritable Bowel Syndrome" American Journal of Gastroenterology 2007 102:2767-2776.

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