Article Text
Abstract
Introduction Patients require an accurate knowledge about placebos and their possible effects to ensure consent for placebo-controlled clinical trials is adequately informed. However, few previous studies have explored patients’ baseline (ie, pretrial recruitment) levels of understanding and knowledge about placebos. The present online survey aimed to assess knowledge about placebos among patients with a history of back pain.
Design A 15-item questionnaire was constructed to measure knowledge about placebos. Additional questions assessed sociodemographic characteristics, duration and severity of back pain, and previous experience of receiving placebos.
Setting Participants recruited from community settings completed the study online.
Results 210 participants completed the questionnaire. 86.7% had back pain in the past 6 months, 44.3% currently had back pain. 4.3% had received a placebo intervention as part of a clinical trial and 68.1% had previously read or heard information about placebos. Overall knowledge of placebos was high, with participants on average answering 12.07 of 15 questions about placebos correctly (SD=2.35). However, few participants correctly answered questions about the nocebo effect (31.9% correct) and the impact of the colour of a placebo pill (55.2% correct).
Conclusions The findings identified key gaps in knowledge about placebos. The lack of understanding of the nocebo effect in particular has implications for the informed consent of trial participants. Research ethics committees and investigators should prioritise amending informed consent procedures to incorporate the fact that participants in the placebo arm might experience adverse side effects.
- Informed consent
- Clinical trials
- Patient perspective
This is an Open Access article distributed in accordance with the terms of the Creative Commons Attribution (CC BY 4.0) license, which permits others to distribute, remix, adapt and build upon this work, for commercial use, provided the original work is properly cited. See: http://creativecommons.org/licenses/by/4.0/
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Footnotes
Contributors MGH and FB conceived and designed the work, with input from CG, GL and PW. MGH collected the data. JGH analysed the data and drafted the manuscript. All authors contributed to data interpretation, revised the work for important intellectual content, approved the version to be published and are accountable for the work.
Funding The study was funded by a grant from Arthritis Research UK (grant reference 20113).
Competing interests None declared.
Patient consent Obtained.
Ethics approval Psychology Ethics Committee, University of Southampton, UK.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement The data reported in this paper may be requested from the corresponding author.
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