Physical possession but not psychological possession of a placebo enhances placebo analgesia

Research output: Other Conference ContributionsPosterpeer-review


Research on placebo analgesia usually shows that people experienced pain reduction after "using" a placebo analgesic. An emerging line of research argued that "merely possessing" a placebo analgesic could induce placebo analgesia under some circumstances (Yeung, Geers, & Kim, 2019; Yeung, Geers, & Colloca, 2020; Yeung & Geers, in press). These research reported that participants who merely possessed (vs. did not possess) a placebo analgesic showed greater pain resilience. The current study aims to clarify the "nature" of analgesic possession, investigating whether physical possession of a tangible placebo analgesic or psychological possession of it via a coupon yields better pain outcomes. Healthy participants (N=90) were presented with a vial of olive (placebo) oil purportedly claimed as a blended essential oil that blocks pain upon nasal inhalation. They were randomized to either physically possess it (physical-possession condition), or possess a coupon to exchange for it (psychological-possession condition) or not possess it (no-possession condition). Participants did a cold-pressor-test and their objective physical pain responses (pain threshold and tolerance) and subjective psychological pain perception (pain intensity, severity and quality) were measured. Results indicated that participants in the physical-possession condition showed better physical pain outcomes than participants in the psychological-possession and no-possession conditions. All participants did not show significant differences in their subjective self-reported pain outcomes. The finding answers a fundamental question about the relative benefit of immediate tangible medication possession over delayed medication possession via prescription. It provides important insights to clinical practice.


Conference3rd International Conference of the Society for Interdisciplinary Placebo Studies (SIPS)
Abbreviated titleSIPS
Country/TerritoryUnited States
Internet address


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