Trial reportPloS one2018
Why do open-label placebos work? A randomized controlled trial of an open-label placebo induction with and without extended information about the placebo effect in allergic rhinitis.
Trial report in PloS one, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 61 papers, 8 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
61 citing papers in PubMed, 8 syntheses or guidelines pooled it, 122 citations in OpenAlex.
- Methodologic challenges of patient reported outcome research: A systematic review of the treatment of cancer related fatigue with open label placebos and the trials.Supportive care in cancer : official journal of the Multinational Association of Supportive Care in Cancer · 2026Pooled it
- Effects of open-label placebos across populations and outcomes: an updated systematic review and meta-analysis of randomized controlled trials.Scientific reports · 2025Pooled it
- A systematic review and meta analysis of open label placebo effects in chronic musculoskeletal pain.Scientific reports · 2025Pooled it
- A systematic qualitative review of ethical issues in open label placebo in published research.Scientific reports · 2025Pooled it
- Low-Level Laser Therapy for Allergic Rhinitis: A Systematic Review and Meta-Analysis.International archives of allergy and immunology · 2024Pooled it
- Open-label placebos-a systematic review and meta-analysis of experimental studies with non-clinical samples.Scientific reports · 2023Pooled it
- Effects of open-label placebos in clinical trials: a systematic review and meta-analysis.Scientific reports · 2021Pooled it
- Placebo Economics: A Systematic Review About the Economic Potential of Utilizing the Placebo Effect.Frontiers in psychiatry · 2019Pooled it
- Can Nocebo Effects Be Reduced via Open- and Closed-Label Counterconditioning?European journal of pain (London, England) · 2026Trial
- Expectation shapes hunger and craving: placebo effects of verbal suggestion on food-related experiences.Annals of behavioral medicine : a publication of the Society of Behavioral Medicine · 2026Trial
- Experimental Approach to Inducing Anti-Histaminergic Placebo Effects: A Randomized Controlled Trial in Healthy Volunteers.Neuroimmunomodulation · 2026Trial
- Roles of administration route, expectation, and belief in placebos in a randomized controlled trial with open-label placebos.Scientific reports · 2025Trial
- It Is Time to Feel Better: How Temporal Information of Placebo Analgesia Affects Our Brain.European journal of pain (London, England) · 2025Trial
- Open-label placebo treatment does not enhance cognitive abilities in healthy volunteers.Scientific reports · 2023Trial
- Task-dependent functional connectivity of pain is associated with the magnitude of placebo analgesia in pain-free individuals.European journal of pain (London, England) · 2023Trial
- A randomized controlled trial of effects of open-label placebo compared to double-blind placebo and treatment-as-usual on symptoms of allergic rhinitis.Scientific reports · 2023Trial
- Effectiveness of Conditioned Open-label Placebo With Methadone in Treatment of Opioid Use Disorder: A Randomized Clinical Trial.JAMA network open · 2023Trial
- Imaginary pills and open-label placebos can reduce test anxiety by means of placebo mechanisms.Scientific reports · 2023Trial
- Lay perspectives of the open-label placebo rationale: a qualitative study of participants in an experimental trial.BMJ open · 2021Trial
- Providing open-label placebos remotely-A randomized controlled trial in allergic rhinitis.PloS one · 2021Trial
1 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
3 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundSeveral studies demonstrated that placebo treatment may have a significant impact on many different symptoms. While in the traditional view concealment of the placebo is essential, recent studies report intriguing evidence that placebos may work even without deception. For example, it has been demonstrated that open-label placebos can improve symptoms in allergic rhinitis. However, the mechanisms of how placebos without concealment work remain unknown. TRIAL
designIn order to examine expectancy effects we conducted a randomized controlled trial (N = 46), in which patients with allergic symptoms received either placebos without deception or no pills at all. In half of those patients we induced positive expectations about the placebo effect. After two weeks we tested whether symptoms and quality of life had changed.
resultsResults revealed that open-label placebos improved allergic symptoms more than the control group. Inducing positive expectations had no effects on the improvement of allergic symptoms (the primary and more objective outcome), but on mental sum scores of the quality of life questionnaire.
conclusionsPlacebos without deception can improve symptoms in allergic rhinitis. Positive expectations do not contribute to the efficacy of open-label placebos, but seem to have an effect on more global and subjective well-being (mental or emotional quality of life). CLINICAL TRIAL REGISTRATION NUMBER: German Clinical Trials Register, DRKS00012303.
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What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.