Medical terminology calls IBS a functional disorder. Functional refers to a condition in which the symptoms are not explainable by any anatomical, pathological or biochemical abnormality or by infection. Doctors are accustomed to rolling their eyes when faced with a patient who has functional symptoms, since functional is medical code for “all in the head.” There is truth in that. The patient’s experience is, in part, in her brain—but, as we will see, not in the pejorative and dismissive sense that the phrase “all in the head” implies.
