A recent randomized controlled trial showed that mindfulness training reduces the severity of IBS in women. Women in the mindfulness group training showed greater reductions in IBS symptom severity at the 3-month follow-up relative to support group. Changes in quality of life, psychological distress, and visceral anxiety were also significantly improved in the in the mindfulness group training than at the 3-month follow-up (Gaylord et al. 2011). Thus, mindfulness training has a substantial therapeutic effect on bowel symptom severity, improves health-related quality of life, and reduces distress.
Hypnotherapy has been demonstrated to have the capacity to normalize visceral sensitivity and modulate motility in GI tract. Hypnosis had specific effects that substantially improved symptoms the symptoms of IBS patients. More than 50% average reduction in IBS severity, substantial reduction in anxiety and depression, improved quality of life, and good maintenance of symptom improvement were shown after the hypnosis treatment (Whorwell et al., 1984). Hypnosis is also effective in the long-term management of FD (Calvert et al. 2002).
OXT released in response to social stimuli may be part of a neuroendocrine substrate which underlies the benefits of positive social experiences. Because of the special properties of OXT, including the fact that it can become conditioned to psychological state or imagery, OXT may mediate the benefits attributed to hypnosis therapy (Uvnas-Moberg et al., 2005; Bryant et al., 2012).
A meta-analysis reviewing the placebo effect of several clinical trials for IBS in adults has found an average placebo response of 40% with a range of 16 to 71% (Patel et al., 2005). Studies on the placebo effect in adult patients with IBS showed that desires and expectations influenced placebo effects (Vase et al. 2005).
The high placebo effect was the result of a high level of expectancy of the subjects and the parents. In addition, a strong family-doctor relationship was observed by a frequent contact between physician and subjects throughout the study (Saps et al. 2009).
In IBS patients that the patient–practitioner relationship is probably the most robust factor contributing to the placebo effect (Kaptchuk et al. 2008).