Trait responsiveness to verbal suggestions predicts nocebo responding: A meta-analysis

Background: Nocebo responding involves the experience of adverse health outcomes in response to contextual cues. These deleterious responses impact numerous features of mental and physical health but are characterized by pronounced heterogeneity. Suggestion is widely recognized as a contributing factor to nocebo responding but the moderating role of trait responsiveness to verbal suggestions (suggestibility) in nocebo responding remains poorly understood.

Objective: We conducted a pre-registered meta-analysis (PROSPERO registration number CRD42023425605) to quantitatively synthesize available research on the relationship between suggestibility and nocebo responding.

Methods: Four electronic databases were searched for original studies involving both the assessment of suggestibility and symptom reports in response to an inactive stimulus.

Results: Of 7729 search results, 10 articles presenting 13 correlations between suggestibility and nocebo responding were analysed. A random-effects meta-analysis revealed a significant, albeit weak, positive correlation, r = .21 [95% CI: .04, .37], between suggestibility and nocebo responses, such that more highly suggestible individuals displayed larger responses. Sensitivity and meta-regression analyses demonstrated that studies of higher methodological quality, including those that maintained experimenter blinding, exhibited stronger effect sizes.

Conclusion: These results corroborate proposals that trait responsiveness to verbal suggestions confers greater response to nocebos and warrants renewed attention to the role of suggestibility in symptom induction and perception.