What techniques might be used to harness placebo effects in non-malignant pain? A literature review and survey to develop a taxonomy

Objectives@ placebo effects can be clinically meaningful but are seldom fully exploited in clinical practice. This review aimed to facilitate translational research by producing a taxonomy of techniques that could augment placebo analgesia in clinical practice. Design: literature review and survey.Methods: we systematically analysed methods which could plausibly be used to elicit placebo effects in 169 clinical and laboratory-based studies involving non-malignant pain, drawn from 7 systematic reviews. In a validation exercise we surveyed 33 leading placebo researchers (M=12 years’ research experience, SD=9.8), who were asked to comment on and add to the draft taxonomy derived from the literature. Results: the final taxonomy defines 30 procedures that may contribute to placebo effects in clinical and experimental research, proposes 60 possible clinical applications, and classifies procedures into 5 domains: the Patient’s Characteristics and Belief (5 procedures and 11 clinical applications); the Practitioner’s Characteristics and Beliefs (2 procedures and 4 clinical applications); the Healthcare Setting (8 procedures and 13 clinical applications); Treatment Characteristics (8 procedures and 14 clinical applications); and the Patient-Practitioner Interaction (7 procedures and 18 clinical applications). Conclusions: the taxonomy provides a preliminary and novel tool with potential to guide translational research aiming to harness placebo effects for patient benefit in practice.