ArticlePsychopharmacology2022
Expectancy in placebo-controlled trials of psychedelics: if so, so what?
Article in Psychopharmacology, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 52 papers, 2 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
52 citing papers in PubMed, 2 syntheses or guidelines pooled it.
- Safety and efficacy of methylenedioxymethamphetamine (MDMA)-assisted psychotherapy in post-traumatic stress disorder: An overview of systematic reviews and meta-analyses.The Australian and New Zealand journal of psychiatry · 2025Pooled it
- In the new era of psychedelic assisted therapy: A systematic review of study methodology in randomized controlled trials.Psychopharmacology · 2024Pooled it
- Dronabinol for nightmares in post-traumatic stress disorder: a randomized controlled trial.Nature medicine · 2026Trial
- Psilocybin-assisted therapy for treatment-resistant major depressive disorder in a public healthcare setting: a randomized controlled trial.Nature medicine · 2026Trial
- Dose-dependent pharmacokinetics and acute effects of intravenous bolus N,N-dimethyltryptamine: double-blind, randomized versus open-label dose-escalation administration study in healthy participants.Translational psychiatry · 2026Trial
- Patient perspectives and experiences with psilocybin treatment for treatment-resistant depression: a qualitative study.Scientific reports · 2024Trial
- Pilot study comparing the effects of high dose THC to high dose psilocybin and placebo in the set and setting of a classic psychedelic therapy session.Psychopharmacology · 2026Article
- Ketamine-induced analgesia and dissociation show distinct behavioral and neural correlates.Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology · 2026Article
- Psychedelics in Mental Health: Opportunities and Challenges.Brain and behavior · 2026Article
- Ten practical suggestions for setting up a psychedelic study.Journal of psychopharmacology (Oxford, England) · 2026Article
- Daily self-assessment within a regimen of microdosing indicates enhanced psychological functioning on microdosing days relative to non-microdosing days.Psychopharmacology · 2026Article
- Measuring and appraising placebo effects in clinical trials: contemporary challenges and approaches in psychiatry.The lancet. Psychiatry · 2026Review
- Challenges with clinical trial participants in studies with classical psychedelics: A position statement from the National Network of Depression Centers' task group on psychedelics and related compounds.Journal of psychopharmacology (Oxford, England) · 2026Article
- Psilocybin effects on brain functional connectivity: a systematic review of fMRI studies.Discover mental health · 2026Review
- Predictors of the Effectiveness of Psychedelics in Treating Depression-A Scoping Review.International journal of molecular sciences · 2026Article
- Ayahuasca and Its Main ComponentBiomedicines · 2026Review
- Causal Inference in Studies with Functional Unmasking: Psychedelics and Beyond.medRxiv : the preprint server for health sciences · 2026Article
- Psychedelic studies in nonhuman primates: Past and future.Molecular psychiatry · 2026Review
- Conceptual analysis of mechanisms and methods in psychedelic clinical trial design: a narrative review.Therapeutic advances in psychopharmacology · 2026Review
- Systems-based psychiatry: insights from psychedelic research on mechanisms of healing.Frontiers in psychiatry · 2026Article
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.
Funding
Abstract
Modern psychedelic research remains in an early phase, and the eventual introduction of psychedelics into clinical practice remains in doubt. In this piece, we discuss the role of blinding and expectancy in psychedelic trials, and place this in a broader historical and contemporary context of blinding in trials across the rest of healthcare. We suggest that premature and uncritical promotion ('hype') of psychedelics as medicines is not only misleading, but also directly influences participant expectancy in ongoing psychedelic trials. We argue that although psychedelic trials are likely to significantly overestimate treatment effects by design due to unblinding and expectancy effects, this is not a unique situation. Placebo-controlled RCTs are not a perfect fit for all therapeutics, and problems in blinding should not automatically disqualify medications from licencing decisions. We suggest that simple practical measures may be (and indeed already are) taken in psychedelic trials to partially mitigate the effects of expectancy and unblinding, such as independent raters and active placebos. We briefly suggest other alternative trial methodologies which could be used to bolster RCT results, such as naturalistic studies. We conclude that the results of contemporary placebo-controlled RCTs of psychedelics should neither be dismissed due to imperfections in design, nor should early data be taken as firm evidence of effectiveness.
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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.