The relationship between psychosocial parameters and outcome in irritable bowel syndrome.

This article reviews the evidence that psychiatric disorders have an adverse influence on the outcome of irritable bowel syndrome (IBS) and relates this to the close relationship between psychological symptoms and severity of abdominal pain, bloating, and diarrhea. Therefore, accurate measurement of psychological symptoms may be an important aspect of trial design for IBS therapy. The importance of psychological distress and health anxiety in differentiating "consulters" and "nonconsulters" for IBS is reviewed. The consequences of excluding from a trial people with certain types of psychiatric disorder or with a known past history of sexual abuse are considered.