No brain, no gain: The role of cognitive processes in irritable bowel syndrome

This article seeks to summarize research supporting the influence of psychological factors in general and cognitive factors in shaping the onset, expression, and outcome of irritable bowel syndrome (IBS). To this end, 6 lines of research are reviewed, with a focus on studies showing (a) the lack of correspondence between IBS symptoms and measured gut motility; (b) IBS patients as a group tend to label visceral sensations negatively and show a lower tolerance for visceral sensations; (c) neuroimaging studies showing abnormalities in central pain processing mechanisms in response to rectal stimuli among IBS vs. healthy controls; (d) high rates of psychiatric comorbidity among treatment seeking IBS patients, particularly of psychiatric disorders marked by cognitive dysfunction (e.g., depression, Generalized Anxiety Disorder); (e) the effects of cognitive factors on IBS and its outcome; and (f) frequency of comorbid functional somatic symptoms whose pathophysiology involves central processing abnormalities (e.g., fibromyalgia, headache). These data provide a strong conceptual foundation for formulating and treating IBS from a cognitive therapy orientation.