Open-label placebos-a systematic review and meta-analysis of experimental studies with non-clinical samples.

Autor: Spille L; Department of Psychology, Occupational Psychology, University of Freiburg, Freiburg, Germany., Fendel JC; Department of Psychosomatic Medicine and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany., Seuling PD; Department of Psychology, Occupational Psychology, University of Freiburg, Freiburg, Germany., Göritz AS; Department of Psychology, Occupational Psychology, University of Freiburg, Freiburg, Germany., Schmidt S; Department of Psychosomatic Medicine and Psychotherapy, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany. stefan.schmidt@uniklinik-freiburg.de.
Jazyk: angličtina
Zdroj: Scientific reports [Sci Rep] 2023 Mar 04; Vol. 13 (1), pp. 3640. Date of Electronic Publication: 2023 Mar 04.
DOI: 10.1038/s41598-023-30362-z
Abstrakt: The use of open-label placebos (OLPs) has shown to be effective in clinical trials. We conducted a systematic review and meta-analysis to examine whether OLPs are effective in experimental studies with non-clinical populations. We searched five databases on April 15, 2021. We conducted separate analyses for self-reported and objective outcomes and examined whether the level of suggestiveness of the instructions influenced the efficacy of OLPs. Of the 3573 identified records, 20 studies comprising 1201 participants were included, of which 17 studies were eligible for meta-analysis. The studies investigated the effect of OLPs on well-being, pain, stress, arousal, wound healing, sadness, itchiness, test anxiety, and physiological recovery. We found a significant effect of OLPs for self-reported outcomes (k = 13; standardized mean difference (SMD) = 0.43; 95% CI = 0.28, 0.58; I 2  = 7.2%), but not for objective outcomes (k = 8; SMD =  - 0.02; 95% CI =  - 0.25, 0.21; I 2  = 43.6%). The level of suggestiveness of the instructions influenced the efficacy of OLPs for objective outcomes (p = 0.02), but not for self-reported outcomes. The risk of bias was moderate for most studies, and the overall quality of the evidence was rated low to very low. In conclusion, OLPs appear to be effective when examined in experimental studies. However, further research is needed to better understand the mechanisms underlying OLPs.
(© 2023. The Author(s).)
Databáze: MEDLINE
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