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Choice and the Placebo Effect: A Meta-analysis.

Biya Tang¹, Kirsten Barnes¹, Andrew Geers²

¹School of Psychology, University of Sydney, A18, Sydney, NSW 2006, Australia.

Annals of Behavioral Medicine : a Publication of the Society of Behavioral Medicine

|January 13, 2022

Summary

This summary is machine-generated.

Providing patients with treatment choice can enhance placebo effects, particularly when the inherent placebo response is low. Further research is needed to confirm these findings in clinical settings.

Keywords:

Choice Personal control Placebo effect Sham treatment

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Area of Science:

Psychology
Medical Research
Behavioral Science

Background:

Choice has been theorized to amplify placebo effects.
Previous research has lacked systematic evaluation of choice's impact on placebo responses.
Understanding moderators of choice's influence on placebo is crucial.

Purpose of the Study:

To quantify the effect size of choice on placebo effects.
To identify moderators influencing the relationship between choice and placebo response.

Main Methods:

Systematic literature search across major databases (Web of Science, PsycINFO, EMBASE, PubMed).
Inclusion of 15 studies (N=1,506) examining health-related outcomes.
Random-effects meta-analysis and meta-regression to determine effect size and moderators.

Main Results:

Choice significantly enhanced placebo effects (Hedges' g = 0.298).
The magnitude of the placebo effect without choice moderated this enhancement.
Greater choice effects were observed when baseline placebo effects were smaller.

Conclusions:

Treatment choice is a viable strategy to augment placebo effects.
The efficacy of choice is more pronounced in conditions with weaker inherent placebo responses.
Translational studies are recommended to validate these findings in clinical practice.