The importance of the therapeutic relationship in IBS was emphasized in a study that investigated the components of the placebo effect and patient-provider interaction in 262 patients with IBS:
At both three and six weeks, the level of improvement in Group 3 was significantly better than Group 2, which in turn was significantly better than Group 1. The conclusion was that placebo effects are significant in IBS and the patient-health care provider interaction is the key part of that effect.
(Source: uptodate.com)