Testing if and when the mere possession of a placebo analgesic cream enhances pain resilience

Background
Yeung et al. (2017) proposed that merely possessing a placebo analgesic may reduce pain. Study 1 directly compared the effect of using vs. possessing a placebo analgesic (compared to controls) on pain-resilience. Second, Geers et al. (2015) found that a placebo analgesic leads to greater pain-reduction for participants without a related prior pain experience. As such, Study 2 examined if mere-possession of a placebo analgesic affects pain with vs. without a related prior-pain-experience.

Methods
Study 1: Participants completed a marketing-survey. Some received a souvenir (a placebo analgesic cream vs. a pain-irrelevant sham cream), some did not (no-cream). Participants who received the placebo analgesic cream either used it or merely possessed it. All participants did a cold-pressor-test (CPT).
Study 2: Participants completed a marketing-survey. Some received a souvenir (a placebo analgesic cream), some did not (no-cream). All participants completed a CPT. In the with-prior-pain condition, participants did a practice-CPT before the marketing-survey to induce a prior-pain-experience. No practice-CPT in the without-prior-pain condition.

Results
Study 1: Participants using the placebo analgesic cream reported higher pain-tolerance and lower pain-intensity than participants in the two control-groups (no-cream, sham-cream). Surprisingly, participants merely possessing the placebo analgesic cream performed equally well as those actually using the cream.
Study 2: Upon possessing a placebo cream, participants without (vs. with) prior-pain-experience reported greater pain-efficacy. This effect was not observed when participants did not possess any cream.

Conclusions
Merely possessing a placebo can enhance pain-resilience to the same extent as applying it. Such mere-possession enhances pain-efficacy when one has no prior-pain-experience.