Main idea: The study demonstrates that providing a placebo and enhancing the encounter remotely is possible, but their effectiveness might be lower in comparison with the previous studies relying on physical patient-provider interaction. The study raises questions for future research about the potential and challenges of remote placebo studies and virtual clinical encounters.
Placebos can reduce physical symptoms even when provided with full honesty and disclosure. Yet, the precise mechanisms underlying the effects of “open-label placebos” (OLPs) have remained the subject of debate. Furthermore, it is unclear whether OLPs are similarly effective when provided remotely, as it is sometimes required, e.g., in the current COVID-19 pandemic.
In a randomized controlled trial, we examined the effects of placebo plus treatment as usual (TAU) compared to TAU alone on symptom reduction in people with allergic rhinitis (N = 54) over the course of two weeks.
Results: The results of the manipulation check confirmed that the clinical encounter was evaluated more positively than the limited encounter, in terms of the perceived warmth of the provider. Participants from all treatment groups showed significant symptom reduction from baseline to two weeks later, but placebo had no incremental effect over TAU. Participants benefitted more from placebo when they did not take any other medication against allergic symptoms than when taking medication on demand. When controlling for baseline symptoms, a significant treatment by encounter interaction was found pointing to greater symptom improvement in the placebo group when the encounter was augmented, whereas the control group improved more when the encounter was limited.