SynthesisPloS one2013
Are treatments more effective than placebos? A systematic review and meta-analysis.
Synthesis in PloS one, 2013. The graph could read no effect estimate from its abstract, so it casts no vote on the map. An erratum has been issued. Cited by 44 papers, 9 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
44 citing papers in PubMed, 9 syntheses or guidelines pooled it, 152 citations in OpenAlex.
- Placebo and nocebo effects and mechanisms associated with pharmacological interventions: an umbrella review.BMJ open · 2023Pooled it
- Placebo administration for dry eye disease: a level I evidence based systematic review and meta-analysis.International journal of clinical pharmacy · 2022Pooled it
- Impact of contextual factors on patient outcomes following conservative low back pain treatment: systematic review.Chiropractic & manual therapies · 2022Pooled it
- Auricular Vagus Neuromodulation-A Systematic Review on Quality of Evidence and Clinical Effects.Frontiers in neuroscience · 2021Pooled it
- Factors Influencing Placebo Responses in Rheumatoid Arthritis Clinical Trials: A Meta-Analysis of Randomized, Double-Blind, Placebo-Controlled Studies.Clinical drug investigation · 2020Pooled it
- Placebo Economics: A Systematic Review About the Economic Potential of Utilizing the Placebo Effect.Frontiers in psychiatry · 2019Pooled it
- Cognitive behavioural therapy (CBT), third-wave CBT and interpersonal therapy (IPT) based interventions for preventing depression in children and adolescents.The Cochrane database of systematic reviews · 2016Pooled it
- The placebo response of injectable GLP-1 receptor agonists vs. oral DPP-4 inhibitors and SGLT-2 inhibitors: a systematic review and meta-analysis.British journal of clinical pharmacology · 2016Pooled it
- Pooled it
- Informing Adults With Back Pain About Placebo Effects: Randomized Controlled Evaluation of a New Website With Potential to Improve Informed Consent in Clinical Research.Journal of medical Internet research · 2019Trial
- Electroacupuncture and splinting versus splinting alone to treat carpal tunnel syndrome: a randomized controlled trial.CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne · 2016Trial
- Two-year follow-up results of fluoroscopic cervical epidural injections in chronic axial or discogenic neck pain: a randomized, double-blind, controlled trial.International journal of medical sciences · 2014Trial
- Magnitude of the placebo response across non-surgical treatment modalities used for knee osteoarthritis: A meta-analysis with meta-regression.Osteoarthritis and cartilage open · 2026Review
- Nature exposure reduces self-reported pain: a systematic review and meta-analysis.Nature. Mental health · 2026Article
- Defining complementary and alternative medicine : Revisiting the Debate and Plea for a Strategy Based on Plausible Effectiveness.Medicine, health care, and philosophy · 2025Article
- No drugs, more sex? And Rock'n Roll: effective non-operative treatments and practical management strategies for older adults with lumbar spinal stenosis.Chiropractic & manual therapies · 2025Review
- Article
- Placebo Effects: Neurological Mechanisms Inducing Physiological, Organic, and Belief Responses-A Prospective Analysis.Healthcare (Basel, Switzerland) · 2024Article
- Advice to the FDA to Improve Its Proposed Guidelines to Rationalize Clinical Trials by Restricting Placebo Control, Preventing Low-Powered Studies, and Disallowing Studies Where Bioavailability Is Not Proven.Pharmaceuticals (Basel, Switzerland) · 2024Review
- Harnessing placebo: Lessons from psychedelic science.Journal of psychopharmacology (Oxford, England) · 2023Review
Corrections and comments
- Erratum issued
Authors and funding
9 authors at 2 institutions in 2 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundPlacebos are widely used in clinical practice in spite of ethical restrictions. Whether such use is justified depends in part on the relative benefit of placebos compared to 'active' treatments. A direct test for differences between placebo and 'active' treatment effects has not been conducted.
objectivesWe aimed to test for differences between treatment and placebo effects within similar trial populations. DATA SOURCES: A Cochrane Review compared placebos with no treatment in three-armed trials (no treatment, placebo, and treatment). We added an analysis of treatment and placebo differences within the same trials. SYNTHESIS
methodsFor continuous outcomes we compared mean differences between placebo and no treatment with mean differences between treatment and placebo. For binary outcomes we compared the risk ratio for treatment benefit (versus placebo) with the risk ratio for placebo benefit (versus no treatment). We conducted several preplanned subgroup analyses: objective versus subjective outcomes, conditions tested in three or more trials, and trials with varying degrees of bias.
resultsIn trials with continuous outcomes (n = 115) we found no difference between treatment and placebo effects (MD = -0.29, 95% CI -0.62 to 0.05, P = 0.10). In trials with binary outcomes (n = 37) treatments were significantly more effective than placebos (RRR = 0.72, 95%CI = 0.61 to 0.86, P = 0.0003). Treatment and placebo effects were not different in 22 out of 28 predefined subgroup analyses. Of the six subgroups with differences treatments were more effective than placebos in five. However when all criteria for reducing bias were ruled out (continuous outcomes) placebos were more effective than treatments (MD = 1.59, 95% CI = 0.40 to 2.77, P = 0.009). CONCLUSIONS AND IMPLICATIONS: Placebos and treatments often have similar effect sizes. Placebos with comparatively powerful effects can benefit patients either alone or as part of a therapeutic regime, and trials involving such placebos must be adequately blinded.
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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.