ArticlePsychopharmacology2018
Double-blind comparison of the two hallucinogens psilocybin and dextromethorphan: similarities and differences in subjective experiences.
Article in Psychopharmacology, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT06772753 (Investigation of Psychedelic Effects in Psychoactive Substances), which is not on this map. Cited by 64 papers, 6 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.
Investigation of Psychedelic Effects in Psychoactive Substances
Who cites it
64 citing papers in PubMed, 6 syntheses or guidelines pooled it, 135 citations in OpenAlex.
- Dextromethorphan Beyond the Cough: Exploring Its Psychedelic Potential: A Systematic Review.CNS drugs · 2026Pooled it
- Therapeutic Use of Psilocybin in Depression: a Systematic Review of Clinical Evidence.Acta neuropsychiatrica · 2025Pooled it
- Synergistic, multi-level understanding of psychedelics: three systematic reviews and meta-analyses of their pharmacology, neuroimaging and phenomenology.Translational psychiatry · 2024Pooled it
- Efficacy of psilocybin for treating symptoms of depression: systematic review and meta-analysis.BMJ (Clinical research ed.) · 2024Pooled it
- A Research Domain Criteria (RDoC)-Guided Dashboard to Review Psilocybin Target Domains: A Systematic Review.CNS drugs · 2022Pooled it
- Dose-response relationships of psilocybin-induced subjective experiences in humans.Journal of psychopharmacology (Oxford, England) · 2021Pooled it
- Enhanced visual contrast suppression during peak psilocybin effects: Psychophysical results from a pilot randomized controlled trial.Journal of vision · 2024Trial
- Comparative acute effects of mescaline, lysergic acid diethylamide, and psilocybin in a randomized, double-blind, placebo-controlled cross-over study in healthy participants.Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology · 2023Trial
- Safety pharmacology of acute LSD administration in healthy subjects.Psychopharmacology · 2022Trial
- Direct comparison of the acute effects of lysergic acid diethylamide and psilocybin in a double-blind placebo-controlled study in healthy subjects.Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology · 2022Trial
- Double-blind comparison of the two hallucinogens psilocybin and dextromethorphan: effects on cognition.Psychopharmacology · 2018Trial
- Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Subcutaneous RE104: A Double-Blind, Randomized, Single Ascending Dose Placebo-Controlled Study.Journal of clinical psychopharmacologyTrial
- Psychedelic Therapy and the Role of Music: A Scoping Review of Quantitative Evidence on Subjective and Objective Outcomes.Brain and behavior · 2026Article
- Integrating the Mystical Experience Questionnaire Into a Broader Psychometric Framework: English Validation of the Psychedelic Experience Scale and Comparison of Psilocybin and LSD Sessions Across Two Controlled Settings.International journal of methods in psychiatric research · 2026Article
- Mindset over molecule: comparing self-transcendent and mystical experiences across recreational psilocybin, MDMA, and cannabis use.BMC psychology · 2026Article
- Pharmacological Properties of Psychedelics with a Special Focus on Potential Harms.Current topics in behavioral neurosciences · 2026Review
- Roland R. Griffiths, psychopharmacology pioneer: Abuse liability, alcohol, nicotine, caffeine, benzodiazepines, and psychedelics.Journal of psychopharmacology (Oxford, England) · 2026Review
- Psilocybin alters visual contextual computations.Nature communications · 2025Article
- Psychedelic Therapy, Positive Emotional Experiences, and the Central Role of Self-Compassion.Research square · 2025Article
- Serotonin and psilocybin activate 5-HTNature communications · 2025Article
4 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
4 authors at 2 institutions in 1 country.
Funding
Abstract
rationaleAlthough psilocybin and dextromethorphan (DXM) are hallucinogens, they have different receptor mechanisms of action and have not been directly compared.
objectiveThis study compared subjective, behavioral, and physiological effects of psilocybin and dextromethorphan under conditions that minimized expectancy effects.
methodsSingle, acute oral doses of psilocybin (10, 20, 30 mg/70 kg), DXM (400 mg/70 kg), and placebo were administered under double-blind conditions to 20 healthy participants with histories of hallucinogen use. Instructions to participants and staff minimized expectancy effects. Various subjective, behavioral, and physiological effects were assessed after drug administration.
resultsHigh doses of both drugs produced similar increases in participant ratings of peak overall drug effect strength, with similar times to maximal effect and time-course. Psilocybin produced orderly dose-related increases on most participant-rated subjective measures previously shown sensitive to hallucinogens. DXM produced increases on most of these same measures. However, the high dose of psilocybin produced significantly greater and more diverse visual effects than DXM including greater movement and more frequent, brighter, distinctive, and complex (including textured and kaleidoscopic) images and visions. Compared to DXM, psilocybin also produced significantly greater mystical-type and psychologically insightful experiences and greater absorption in music. In contrast, DXM produced larger effects than psilocybin on measures of disembodiment, nausea/emesis, and light-headedness. Both drugs increased systolic blood pressure, heart rate, and pupil dilation and decreased psychomotor performance and balance.
conclusionsPsilocybin and DXM produced similar profiles of subjective experiences, with psilocybin producing relatively greater visual, mystical-type, insightful, and musical experiences, and DXM producing greater disembodiment.
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.