Irritable bowel syndrome (IBS) is a condition characterized by abdominal symptoms originating in the intestines and in some way related to the digestive process, often in a manner that is not entirely predictable or is generally described as “unpredictable” or “temperamental.”
Most cases involve the colon, hence the expression “irritable colon.” The most frequent symptoms are a feeling of fullness or abdominal tension, as well as diffuse or localized bloating. When localized, it typically occurs in the upper right abdomen, as though a bubble were pressing beneath the liver, or in the upper left abdomen, as though something were pressing beneath the heart. Bowel movements are irregular, as though the intestine were inexplicably “irritable,” alternating between constipation or a feeling of “blockage” and bouts of diarrhea, often fragmented and accompanied or preceded by cramp-like pain and spasms. The term “spastic colitis” is often used incorrectly to refer to this type of syndrome.
There is no inflammatory condition of the colon. Instead, there are abnormalities in the distribution of pressure across the various segments, abnormalities in muscle tone and secretions, and, above all, an overall abnormal, disrupted, or paradoxical coordination of the different intestinal segments.
Over time, people with irritable bowel syndrome develop a kind of “direct line” with their intestines, in the sense that they form a sort of mental image of the different intestinal segments, their dimensions, their degree of distension or contraction, and the type of material (solid, liquid, or gas) moving through them. In reality, these sensations often do not correspond to actual “maps” of the intestines; they are simply a representation generated by the brain that does not faithfully reproduce the anatomical situation. For example, the sensation of a “tight bubble” does not necessarily correspond to a large accumulation of gas. Increased sensitivity of the intestinal wall alone may be sufficient to generate such a sensation.
People with irritable bowel syndrome may have difficulty organizing their social lives because social activities often involve lunches, dinners, gatherings around a table, or refreshments.
Irritable bowel syndrome interferes with dietary freedom and leads people to become convinced that certain foods cause intolerance-like reactions. These are generally foods that place greater demands on digestion or stimulate intestinal motility or secretions, but there is no specific pattern. Over time, the rules for reliably avoiding symptoms tend to become confused, while other factors—such as the environment, lifestyle, and mood—begin to make their influence apparent.
All bodily disorders that fail to resolve to some extent can lead to demoralization. Irritable bowel syndrome, however, appears to do so particularly strongly. Suffice it to say that true inflammatory colitis is associated with a lifetime risk of depression of around 15%, whereas irritable bowel syndrome is associated with a risk of around 60%.
Irritable bowel syndrome is the classic example of a psychosomatic disorder, although this term is not entirely correct. It is not a psychological disturbance that expresses itself through the intestines, but rather an altered—or progressively altered—brain function whose first “reflex” expression outside the brain occurs in the intestines, just as it may occur in the skin, for example.
People with irritable bowel syndrome usually also experience, or will go on to experience, symptoms of anxiety and depression. Some patients, however, do not consider themselves either depressed or anxious, but display temperament characteristics of an anxious nature that have never in themselves constituted a problem. It is possible that, in these cases, the intestinal symptoms are the first warning sign of an evolving alteration in nervous-system function, because these individuals have the intestinal tract as their most direct channel for nervous-system reflex responses.
In some cases, irritable bowel syndrome is associated with bodily symptoms more typically associated with anxiety, such as palpitations, sweating, a feeling of faintness, a false sense of “low blood pressure,” or a false sensation of dizziness or vertigo. In these cases, there may be genuine “attacks” dominated by fear, a sense of losing control over bodily functions, and an impending feeling of becoming unwell, followed or accompanied by bouts of diarrhea and exhaustion.
Irritable bowel syndrome is a treatable condition. There are medications that can modify intestinal motility, as well as certain antidepressants and antipsychotic medications that can reduce intestinal irritability, allowing for a freer diet without unpleasant intestinal “surprises,” or at least reducing the severity of symptoms and the frequency of episodes.