Psychological abnormalities in patients with irritable bowel syndrome.

Irritable bowel syndrome (IBS) is a group of functional bowel disorders with different pathophyiological mechanisms but some common clinical features. It can be conceptualized within the biopsychosocial model of illness as a dysregulation of brain-gut axis and its relationships with psychosocial and environmental variables. Using advanced neuro-imaging techniques, it has been found that some brain centers (anterior cingulate cortex, limbic system, locus ceruleus) are active in mediating gut signals and that visceral hyperalgesia mediates perceptual sensitivity. Using new criteria for diagnosing psychosocial components of somatic illnesses, persistent somatization has been found as one of the main psychological factors that contributes to persistence of symptoms and poor treatment outcome in patients with IBS. Other psychological variables influencing symptom reporting have been identified in the constructs of health-care seeking, abuse, somatosensory amplification, and alexithymia. From a psychological viewpoint, IBS may be conceived as an abnormal cognitive processing of emotional and visceral stimuli, a tendency to perceive somatic stimuli as evidence of symptoms of disease, and to seek repeated and often unnecessary medical care.