from Placebo interventions for all clinical conditions
Asbjørn Hróbjartsson1, Peter C Gøtzsche1
1The Nordic Cochrane Centre, Rigshospitalet, Copenhagen, Denmark
Contact address: Asbjørn Hróbjartsson, The Nordic Cochrane Centre, Rigshospitalet, Blegdamsvej 9, 3343, Copenhagen, 2100, Denmark. firstname.lastname@example.org
Editorial group: Cochrane Consumers and Communication Group.
Publication status and date: New search for studies and content updated (conclusions changed), published in Issue 1, 2010.
Review content assessed as up-to-date: 10 November 2009.
Citation: Hróbjartsson A, Gøtzsche PC. Placebo interventions for all clinical conditions. Cochrane Database of Systematic Reviews 2010, Issue 1. Art. No.: CD003974. DOI: 10.1002/14651858.CD003974.pub3.
Copyright © 2010 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
Plain language summary
Placebo interventions for all clinical conditions
Placebo interventions are often claimed to substantially improve many clinical conditions. However, most reports on effects of placebos are based on unreliable studies that have not randomised patients to placebo or no treatment.
We studied the effect of placebo treatments by reviewing 202 trials comparing placebo treatment with no treatment covering 60 healthcare problems. In general, placebo treatments produced no major health benefits, although on average they had a modest effect on outcomes reported by patients, such as pain. However, the effect on pain varied from large to non-existent, even in well-conducted trials. Variations in the effect of placebo was partly explained by variations in how trials were conducted, the type of placebo used, and whether patients were informed that the trial involved placebo.
I say: if it's not an intervention it's 'no treatment'.