Placebo by proxy expectations toward acupuncture change over time: a survey comparing parental expectations to acupuncture pre- and postoperatively

Ingrid Liodden,Are Hugo Pripp,Arne Johan Norheim

doi:10.1186/s12906-018-2248-z

Abstract

BackgroundPatients entering a treatment have expectancy to outcome based on their previous experience, the information received, and the credibility of the treatment. Once the treatment has started, patients may detect and interpret contextual cues and somatic state. Influenced and conditioned by positive or negative interpretations, their reappraisal may improve or worsen the treatment outcome. The aims were to investigate whether parental pre-treatment expectancies towards acupuncture differ compared to post-treatment expectancies, and assess predictors for possible change of parental expectancy. Further, we wanted to explore whether the change correlates with the treatment outcome, i.e. postoperative vomiting in children.MethodsTwo hundred and eighty-two parents completed per- and 24 h postoperatively a survey on their expectancy to acupuncture treatment for alleviation of postoperative vomiting in children. The survey was embedded in a randomised controlled trial.ResultsParental expectancy to acupuncture treatment changed over time. The changes were predicted by several variables such as children’s gender, parents’ age and education, previous experiences, and assignment to treatment group. The strongest predictor was parental anxiety to their child undergoing surgery. Further, the change of parental expectancy was correlated with postoperative vomiting.ConclusionsAnxious parents are prone to change their expectancy in a positive direction during the treatment period, which in turn may improve treatment outcome. Acupuncture therapists in clinical practice should pay a special attention to the potential that lies here, and acknowledge parental anxiety as a possible facilitator, and not a barrier, to elicit placebo by proxy effects. Further research to expand the findings of the present study into other treatments is in order. Future research should also provide more knowledge about how parental expectancy changes over time, and how different factors predict and produce change of parental expectancy.Trial registrationClinicalTrials.gov NCT01729052. Registered November 20, 2012.

Highlights

Patients entering a treatment have expectancy to outcome based on their previous experience, the information received, and the credibility of the treatment
Using a stepwise multivariable regression analysis, we found that parents of female children, increasing parental anxiety, and parents having children assigned to acupuncture group, predicted a positive change of how logical acupuncture seemed to them
We suggest that anxious parents are prone to change their expectancy in a positive direction during the treatment period, which may in turn improve treatment outcome

Summary

Introduction

Patients entering a treatment have expectancy to outcome based on their previous experience, the information received, and the credibility of the treatment. Influenced and conditioned by positive or negative interpretations, their reappraisal may improve or worsen the treatment outcome. Several psychological processes are involved in placebo effects, such as expectancy to treatment [1] and cognitive reinterpretation in the form of reappraisal, which involves “reinterpreting the meaning of affective stimuli in ways that alter [their] emotional impact” [2]. These two processes may contribute to creating succeeding biological and physiological reactions and may play important roles to the magnitude of treatment effects. The phenomenon placebo by proxy is underappreciated and rarely discussed, Grelotti and Kaptchuk [6] contend that placebo by proxy probably occurs as frequently as other placebo effects and may have great implications

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Conclusion