Is Open Labelled Placebo a Plausible Treatment for Patients with Chronic Pain? A Scoping Review

Abstract

Introduction: Chronic pain is a prevalent global health challenge, affecting approximately 30% of the population and imposing significant socio-economic burdens. Despite the broad spectrum of available treatments, the placebo effect is the most significant factor influencing treatment efficacy. Research has shown that placebo, even when administered openly, remained effective on physical and psychological outcomes. Objectives: To examine the efficacy, mechanisms, and practical applications of open-label placebos (OLP) and conditioned open-label placebos (COLP) in chronic pain management. Methods: Following PRISMA guidelines for scoping reviews, we conducted a PIO-search and a terminology-focused search in PubMed, Cochrane, Embase, and PsycINFO databases for studies published prior to March 2024. Inclusion criteria encompassed per-reviewed records, investigating the impact of OLP on chronical pain. Moreover, records were included when investigating COLP on pain management. Exclusion criteria encompassed non-empirical records. Data were charted, synthesized, and assessed for risk of bias by one researcher. Results: In total, 1,432 records were screened for eligibility. The review included 16 RCTs, 3 reviews, and 7 qualitative studies. The overall evidential quality was moderate. OLP had a statistically significant effect reducing pain intensity and medication use, while improving function. Clinical relevance remained inconclusive, with most prominent findings on chronic secondary pain conditions, such as knee osteoarthritis and irritable bowel syndrome. However, the efficacy in chronic primary low back pain remained controversial and one study showed an increase in complementary and alternative treatments. COLP showed potential in reducing opioid consumption post-surgery, but its efficacy seemed diminished in chronic pain patients. Moreover, patients were more likely to accept OLP and COLP as potential treatment options when proven effective or when no other treatment was available. Providers raised concerns on ethics, missing guidelines, and potential mistrust in the healthcare system and scientifical approaches. Conclusions: OLP and COLP presented controversial but cost-effective treatments for chronic pain, where efficacy may depend on pain mechanisms. Further research is needed to standardise methods and guidelines, explore long-term effects, assess efficacy across different chronic pain conditions, and address ethical considerations for clinical integration.

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A master programme thesis from Aalborg University

Is Open Labelled Placebo a Plausible Treatment for Patients with Chronic Pain? A Scoping Review