Evidence map›Paper›PMID 30062577›Full record

Trial reportPsychopharmacology2018

Double-blind comparison of the two hallucinogens psilocybin and dextromethorphan: effects on cognition.

Frederick S Barrett, Theresa M Carbonaro, Ethan Hurwitz, Matthew W Johnson, Roland R Griffiths

Open access · greenAbstract readRandomized Controlled Trial
PubMed Full text at PMC Publisher
In one paragraph

Trial report in Psychopharmacology, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 54 papers, 7 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
54citing papers in PubMed, 7 pooled it
6.6field-weighted citation impact, top 3% of its field
1 · What the graph read from 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.

2 · The registry

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.

3 · Its place in the literature

Who cites it

54 citing papers in PubMed, 7 syntheses or guidelines pooled it, 103 citations in OpenAlex.

  1. Pooled it
  2. Pooled it
  3. Pooled it
  4. Pooled it
  5. Impact of psilocybin on cognitive function: A systematic review.Psychiatry and clinical neurosciences · 2024
    Pooled it
  6. Pooled it
  7. Pooled it
  8. Trial
  9. Trial
  10. Trial
  11. Review
  12. Review
  13. Article
  14. Review
  15. Causal Inference in Studies with Functional Unmasking: Psychedelics and Beyond.medRxiv : the preprint server for health sciences · 2026
    Article
  16. Review
  17. Review
  18. Review
  19. Review
  20. Observational
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors at 1 institution in 1 country.

Frederick S BarrettBehavioral Pharmacology Research Unit, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 5510 Nathan Shock Dr., Baltimore, MD, 21224, USA. fbarrett@jhmi.edu.ORCID http://orcid.org/0000-0001-7443-3237
Theresa M CarbonaroBehavioral Pharmacology Research Unit, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 5510 Nathan Shock Dr., Baltimore, MD, 21224, USA.
Ethan HurwitzBehavioral Pharmacology Research Unit, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 5510 Nathan Shock Dr., Baltimore, MD, 21224, USA.
Matthew W JohnsonBehavioral Pharmacology Research Unit, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 5510 Nathan Shock Dr., Baltimore, MD, 21224, USA.
Roland R GriffithsBehavioral Pharmacology Research Unit, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 5510 Nathan Shock Dr., Baltimore, MD, 21224, USA.
Johns Hopkins University · US

Funding

HUMAN BEHAVIORAL PHARMACOLOGY OF SUBSTANCE ABUSET32DA007209 · NIDA · JOHNS HOPKINS UNIVERSITY · PI Eric C. Strain, Elise M Weerts · 1985 to 2026
$12.9M
Human Clinical Pharmacology of Emerging Drugs of Abuse (Club Drugs)R01DA003889 · NIDA · JOHNS HOPKINS UNIVERSITY · PI GRIFFITHS, ROLAND R · 1985 to 2017
$7.6M
Development of a Prospective Memory Intervention to Reduce Drug Use and HIV RiskR01DA035277 · NIDA · JOHNS HOPKINS UNIVERSITY · PI JOHNSON, MATTHEW WAYNE · 2013 to 2018
$2.0M
Measurement of persisting changes in emotional brain functioning produced by psilocybinR03DA042336 · NIDA · JOHNS HOPKINS UNIVERSITY · PI BARRETT, FREDERICK STREETER · 2016 to 2016
$260k
National Institute on Drug Abuse R01DA035277National Institute on Drug Abuse R01DA03889National Institute on Drug Abuse R03DA042336National Institute on Drug Abuse T32DA007209NIDA NIH HHS R01 DA003889NIDA NIH HHS R01 DA035277NIDA NIH HHS R03 DA042336NIDA NIH HHS T32 DA007209
6 · The paper itself

Abstract

objectivesClassic psychedelics (serotonin 2A receptor agonists) and dissociative hallucinogens (NMDA receptor antagonists), though differing in pharmacology, may share neuropsychological effects. These drugs, however, have undergone limited direct comparison. This report presents data from a double-blind, placebo-controlled within-subjects study comparing the neuropsychological effects of multiple doses of the classic psychedelic psilocybin with the effects of a single high dose of the dissociative hallucinogen dextromethorphan (DXM).

methodsTwenty hallucinogen users (11 females) completed neurocognitive assessments during five blinded drug administration sessions (10, 20, and 30 mg/70 kg psilocybin; 400 mg/70 kg DXM; and placebo) in which participants and study staff were informed that a large range of possible drug conditions may have been administered.

resultsGlobal cognitive impairment, assessed using the Mini-Mental State Examination during peak drug effects, was not observed with psilocybin or DXM. Orderly and dose-dependent effects of psilocybin were observed on psychomotor performance, working memory, episodic memory, associative learning, and visual perception. Effects of DXM on psychomotor performance, visual perception, and associative learning were in the range of effects of a moderate to high dose (20 to 30 mg/70 kg) of psilocybin.

conclusionsThis was the first study of the dose effects of psilocybin on a large battery of neurocognitive assessments. Evidence of delirium or global cognitive impairment was not observed with either psilocybin or DXM. Psilocybin had greater effects than DXM on working memory. DXM had greater effects than all psilocybin doses on balance, episodic memory, response inhibition, and executive control.

Indexed as

AdultAssociation LearningCognitionDextromethorphanDose-Response Relationship, DrugDouble-Blind MethodFemaleHallucinogensHumansMaleMemory, Short-TermPsilocybinPsychomotor PerformanceVisual PerceptionYoung AdultDextromethorphanHallucinogensPsilocybinCognitionDextromethorphanHallucinogenPsilocybinPsychedelic drug

Identifiers

PMID30062577
PMCPMC6162157
OpenAlexW2886435130

What OpenQuestion holds

Textmetadata
LicenceTDM
Read underepoch 390

Registered trials

None linked

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.