Research study · Pain · 2023
Association between personality traits and placebo effects: a preregistered systematic review and meta-analysis
Verified on PubMed Systematic review or meta-analysis
A 2023 meta-analysis in Pain in personality. No evidence of associations between 10 different personality traits (including anxiety, optimism, reward responsiveness, and empathy) and the magnitude of placebo effects. This study suggests that basing expectations of a patient's response to treatment on their personality traits is not supported by current evidence, prompting clinicians and researchers.
In plain language
Study overview
This systematic review and meta-analysis demonstrates that standard personality traits do not reliably predict placebo responsiveness, challenging the clinical assumption of a 'placebo personality'. Clinicians and researchers should look to situational, contextual, learning-based, or neurobiological factors rather than baseline personality when assessing variability in patient response to inert treatments or therapies.
Findings
No evidence of associations between 10 different personality traits (including anxiety, optimism, reward responsiveness, and empathy) and the magnitude of placebo effects. Equivalence tests supported the absence of any meaningful medium-to-large effects (r > 0.3) of personality on placebo responses. Subgroup analyses showed no significant moderating effects of condition (pain vs non-pain) or placebo manipulation method (conditioning vs non-conditioning).
The deeper readScientific analysis
Placebo effects are ubiquitous yet highly variable between individuals and therefore strongly affect clinical trial outcomes such as pain relief. It is unclear whether dispositional psychological traits influence responsiveness to placebo. This preregistered meta-analysis and systematic review synthesized the literature investigating the association between personality traits and placebo effects. Based on 21 studies with 798 participants, we performed formal meta-analyses for 10 different personality traits, including behavioral inhibition, fun seeking, goal-drive persistence, reward responsiveness, empathic concern, empathic fantasy, perspective-taking, personal distress, optimism, and anxiety. We did not find evidence of associations between any of these traits and magnitude of placebo effects, which was supported by equivalence tests. Furthermore, we did not find evidence for moderating factors such as placebo manipulation type (conditioning or nonconditioning) or condition (pain or nonpain). These findings challenge the notion that personality influences responsiveness to placebos and contradict its utility for identifying placebo "responders" and "nonresponders."
The paper
Citation
Kang H, Miksche MS, Ellingsen DM Association between personality traits and placebo effects: a preregistered systematic review and meta-analysis. Pain (2023). PubMed 35947877 · DOI
Limitations the authors noted
Limited number of eligible studies and sample sizes may have been underpowered to detect very small effects. Potential risk of bias due to suboptimal experimental blinding (mostly single-blinded designs) in the underlying literature. Exclusion of studies lacking a no-treatment control condition or utilizing stratification approaches.
In practice
Why this matters
This study suggests that basing expectations of a patient's response to treatment on their personality traits is not supported by current evidence, prompting clinicians and researchers to focus more on situational factors rather than individual dispositions when assessing placebo effects.
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Reviewed by Dr. Caplan on September 23, 2026.
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