SynthesisEuropean journal of clinical investigation2022
Influence of placebo effect in mental disorders research: A systematic review and meta-analysis.
Synthesis in European journal of clinical investigation, 2022. 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 14 papers, 4 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
14 citing papers in PubMed, 4 syntheses or guidelines pooled it, 29 citations in OpenAlex.
- Influence of Lycopene Intake on Mental Health: A Systematic Review of Randomized Controlled Trials (RCTs).Nutrients · 2025Pooled it
- Placebo effects in randomized trials of pharmacological and neurostimulation interventions for mental disorders: An umbrella review.Molecular psychiatry · 2024Pooled it
- Placebo and nocebo effects and mechanisms associated with pharmacological interventions: an umbrella review.BMJ open · 2023Pooled it
- Influence of placebo effect in mental disorders research: A systematic review and meta-analysis.European journal of clinical investigation · 2022Pooled it
- Impact of nano-selenium supplementation add-on sertraline on depressive symptoms and oxidative stress in patients with major depressive disorder: a triple-blind randomized controlled trial.Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine · 2026Trial
- Investigating the feasibility and safety of transcranial infraslow gray noise stimulation as a potential treatment for generalized anxiety disorder.Scientific reports · 2025Trial
- Transcutaneous Auricular Vagus Nerve Stimulation for the Treatment of Myoarthropathic Symptoms Associated With Temporomandibular Disorders-A Pilot Randomised Controlled Trial.Journal of oral rehabilitation · 2025Trial
- Efficacy of the mHealth App Intellect in Improving Subclinical Obsessive-Compulsive Disorder in University Students: Randomized Controlled Trial With a 4-Week Follow-Up.JMIR mHealth and uHealth · 2024Trial
- Personalized machine learning guided intervention for optimizing lifestyle behaviors in depression: a pilot study.NPP - digital psychiatry and neuroscience · 2026Article
- Article
- Placebo, Nocebo, and Machine Learning: How Generative AI Could Shape Patient Perception in Mental Health Care.JMIR mental health · 2025Article
- "Happiness tree": a thematic art-based group counseling method for enhancing positive psychological traits in Chinese college students.Frontiers in psychology · 2025Article
- Effect of Dancing Interventions on Depression and Anxiety Symptoms in Older Adults: A Systematic Review and Meta-Analysis.Behavioral sciences (Basel, Switzerland) · 2024Review
- Corrigendum.European journal of clinical investigation · 2022Article
Corrections and comments
- Erratum issuedCorrigendum.2022
Authors and funding
4 authors at 1 institution in 1 country.
Funding
Abstract
backgroundRandomized controlled trials (RCT) in mental disorders research commonly use active control groups including psychotherapeutic shams or inactive medication. This meta-analysis assessed whether placebo conditions (active controls) had an effect compared to no treatment or usual care (passive controls).
methodsPubMed, Scopus, PsycINFO, PsycARTICLES, Ovid, the Cochrane Central Register of Controlled Trials and Web of Science were searched from inception to April 2021 and reference lists of relevant articles. Three-arm RCTs, including active and passive control groups, were selected. Where individual standardized mean difference (SMD) was calculable, random effects meta-analyses were performed to estimate an overall effect size with 95% confidence intervals (CI) comparing active vs passive controls. Heterogeneity was assessed using I² statistic and meta-regression. Funnel asymmetry was evaluated using Egger's test (Prospero registration: CRD42021242940).
results24 articles with 25 relevant RCTs were included in the review, of which 11 studies were of high risk of bias. There was an improvement in outcomes favouring the placebo conditions, compared to passive controls, overall (25 studies, SMD 0.24, 95% CI 0.06-0.42, I² = 43%) and in subgroups with anxiety (SMD 0.45, 95% CI 0.07-0.84, I² = 59%) or depression (SMD 0.22, 95% CI 0.04-0.39, I² = 0%). Meta-regression did not show a significant explanation for heterogeneity. Egger's test showed no asymmetry (p = .200).
conclusionsA small placebo effect was observed in mental disorders research overall, and in patients with anxiety or depression. These findings should be interpreted with caution in the light of heterogeneity and risk of bias.
Indexed as
Identifiers
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.