A recent meta-study in the World Journal of Gastroenterology (March 28 2017) – Systematic review: The placebo effect of psychological interventions in the treatment of irritable bowel syndrome
Aim – “To determine the placebo response rate associated with different types of placebo interventions used in psychological intervention studies for irritable bowel syndrome.” (Six studies, with a total of 555 patients met the inclusion criteria.)
… and the placebo effect, unsurprisingly, figures significantly:
“Contrary to our expectations, the PRR (Placebo Response Rate) in studies on psychological interventions was comparable to that in studies on pharmacological, dietary and alternative medical interventions.”
Download the whole study in PDF here.