Depressive DisordersHealthy VolunteersTreatment-Resistant Depression (TRD)Anxiety DisordersObsessive-Compulsive Disorder (OCD)Substance Use Disorders (SUD)Palliative & End-of-Life DistressSafety & Risk ManagementInterpersonal Functioning & Social ConnectednessPsilocybin

The effects of psilocybin on cognitive and emotional functions in healthy participants: Results from a phase 1, randomised, placebo-controlled trial involving simultaneous psilocybin administration and preparation

In the largest randomised, double‑blind, placebo‑controlled phase 1 trial of psilocybin to date (n=89), healthy participants received a single oral dose of 10 mg or 25 mg psilocybin (or placebo) simultaneously in small groups with one‑to‑one psychological support. Both doses were generally well tolerated with no serious adverse events and produced no clinically relevant short‑ or long‑term differences in cognitive performance (CANTAB global and domain scores) or emotional processing compared with placebo.

Authors

  • James Rucker
  • Allan Young
  • Ekaterina Malievskaia

Published

Journal of Psychopharmacology
individual Study

Abstract

Background

Psilocybin, a psychoactive serotonin receptor partial agonist, has been reported to acutely reduce clinical symptoms of depressive disorders. Psilocybin’s effects on cognitive function have not been widely or systematically studied.

Aim

The aim of this study was to explore the safety of simultaneous administration of psilocybin to healthy participants in the largest randomised controlled trial of psilocybin to date. Primary and secondary endpoints assessed the short- and longer-term change in cognitive functioning, as assessed by a Cambridge Neuropsychological Test Automated Battery (CANTAB) Panel, and emotional processing scales. Safety was assessed via endpoints which included cognitive function, assessed by CANTAB global composite score, and treatment-emergent adverse event (TEAE) monitoring.

Methods

In this phase 1, randomised, double-blind, placebo-controlled study, healthy participants ( n = 89; mean age 36.1 years; 41 females, 48 males) were randomised to receive a single oral dose of 10 or 25 mg psilocybin, or placebo, administered simultaneously to up to six participants, with one-to-one psychological support – each participant having an assigned, dedicated therapist available throughout the session.

Results

In total, 511 TEAEs were reported, with a median duration of 1.0 day; 67% of all TEAEs started and resolved on the day of administration. There were no serious TEAEs, and none led to study withdrawal. There were no clinically relevant between-group differences in CANTAB global composite score, CANTAB cognitive domain scores, or emotional processing scale scores.

Conclusions

These results indicate that 10 mg and 25 mg doses of psilocybin were generally well tolerated when given to up to six participants simultaneously and did not have any detrimental short- or long-term effects on cognitive functioning or emotional processing.

Available with Blossom Pro

Research Summary of 'The effects of psilocybin on cognitive and emotional functions in healthy participants: Results from a phase 1, randomised, placebo-controlled trial involving simultaneous psilocybin administration and preparation'

Introduction

Psilocybin is a naturally occurring psychedelic and a partial agonist at serotonin receptors, principally 5-HT2A and 5-HT1A. Earlier clinical and preclinical studies have suggested psilocybin can produce rapid changes in mood and affect and may reduce symptoms in conditions such as treatment-resistant depression, anxiety in terminal illness, OCD and substance use disorders. However, much of the evidence to date has come from small, often open-label studies or trials lacking placebo control, and there remains limited systematic evidence about psilocybin's effects on cognitive functioning and longer-term emotional and social cognition outcomes. Rucker and colleagues set out to evaluate the safety, feasibility and cognitive and emotional effects of single oral doses of psilocybin (10 mg and 25 mg) compared with placebo in healthy volunteers. The study additionally explored a model of simultaneous administration — dosing up to six participants at once with individual psychological support — as a potentially more time- and cost-efficient approach to delivering therapy. The authors aimed to measure short- and longer-term changes in cognitive domains using the CANTAB battery and in emotional/social processing with multiple standardised tests, while systematically capturing adverse events over a 12-week follow-up.

Expert Research Summaries

Go Pro to access AI-powered section-by-section summaries, editorial takes, and the full research toolkit.

Full Text PDF

Full Paper PDF

Create a free account to open full-text PDFs.

Study Details

References (26)

Papers cited by this study that are also in Blossom

The therapeutic potential of psychedelic drugs: past, present, and future

Carhart-Harris, R. L., Goodwin, G. M. · Neuropsychopharmacology (2017)

Psilocybin with psychological support for treatment-resistant depression: six-month follow-up

Carhart-Harris, R. L., Bolstridge, &. M., Day, C. M. J. et al. · Psychopharmacology (2017)

Neural correlates of the psychedelic state as determined by fMRI studies with psilocybin

Carhart-Harris, R. L., Erritzoe, D., Williams, T. et al. · PNAS (2012)

Ayahuasca dimethyltryptamine, and psychosis: a systematic review of human studies

Dos Santos, R. G., Hallak, J. E., Bouso, J. C. · Therapeutic Advances in Psychopharmacology (2017)

Psilocybin and MDMA reduce costly punishment in the Ultimatum Game

Gabay, A. S., Carhart-Harris, R. L., Mazibuko, N. et al. · Scientific Reports (2018)

Pilot study of psilocybin treatment for anxiety in patients with advanced-stage cancer

Grob, C. S., Danforth, A. L., Chopra, G. S. et al. · JAMA Psychiatry (2011)

Multiple receptors contribute to the behavioral effects of indoleamine hallucinogens

Halberstadt, A. L., Geyer, M. A. · Neuropharmacology (2011)

Show all 26 references
Psychedelic Agents in Creative Problem-Solving: A Pilot Study

Harman, W. W., McKim, R. H., Mogar, R. E. et al. · Psychological Reports (1966)

Pilot study of the 5-HT2AR agonist psilocybin in the treatment of tobacco addiction

Johnson, M. W., Garcia-Romeu, A., Cosimano, M. P. et al. · Journal of Psychopharmacology (2014)

Reactions to psilocybin administered in a supportive environment

Leary, T., Litwin, G. H., Metzner, R. · Journal of Nervous and Mental Disease (1977)

Hallucinogen persisting perception disorder and the serotonergic system: A comprehensive review including new MDMA-related clinical cases

Litjens, R. P. W., Brunt, T. M., Alderliefste, G. et al. · European Neuropsychopharmacology (2014)

Psychedelic effects of psilocybin correlate with serotonin 2A receptor occupancy and plasma psilocin levels

Madsen, M. K., Fisher, P. M., Burmester, D. et al. · Neuropsychopharmacology (2019)

Sub-Acute Effects of Psilocybin on Empathy, Creative Thinking, and Subjective Well-Being

Mason, N. L., Mischler, E., Uthaug, M. V. et al. · Journal of Psychoactive Drugs (2019)

136 cited
Safety, Tolerability, and Efficacy of Psilocybin in 9 Patients With Obsessive-Compulsive Disorder

Moreno, F. A., Wiegand, C. B., Taitano, E. K. et al. · Journal of Clinical Psychiatry (2006)

The pharmacology of psilocybin

Passie, T., Seifert, J., Schneider, U. et al. · Addiction Biology (2002)

Effect of psilocybin on empathy and moral decision-making

Pokorny, T., Preller, K. H., Kometer, M. et al. · International Journal of Neuropsychopharmacology (2017)

155 cited
Effects of serotonin 2A/1A receptor stimulation on social exclusion processing

Preller, K. H., Pokorny, D., Hock, A. et al. · PNAS (2016)

Psychedelics in the treatment of unipolar mood disorders: a systematic review

Rucker, J., Young, A. H., Jelen, L. A. et al. · Journal of Psychopharmacology (2016)

75 cited
Psilocybin induces schizophrenia-like psychosis in humans via a serotonin-2 agonist action

Vollenweider, F. X., Vollenweider-Scherpenhuyzen, M. F. I., Bäbler, A. et al. · NeuroReport (1998)

Cited By (24)

Papers in Blossom that reference this study

Compass Psychological Support Model for COMP360 Psilocybin Treatment of Serious Mental Health Conditions

Kirlic, N., Lennard-Jones, M., Atli, M. et al. · American Journal of Psychiatry (2025)

Single-Dose Synthetic Psilocybin With Psychotherapy for Treatment-Resistant Bipolar Type II Major Depressive Episodes

Aaronson, S. T., van der Vaart, A., Miller, T. et al. · JAMA Psychiatry (2024)

71 cited
The Influence of Psilocybin on Subconscious and Conscious Emotional Learning

Casanova, A. F., Ort, A., Smallridge, J. W. et al. · iScience (2024)

Show all 24 papers
Psilocybin-assisted therapy for depression: A systematic review and meta-analysis

Haikazian, S., Chen-Li, D., Johnson, D. et al. · Psychiatry Research (2023)

Psilocybin for treatment resistant depression in patients taking a concomitant SSRI medication

Goodwin, G. M., Croal, M., Feifel, D. et al. · Neuropharmacology (2023)

Investigation of self-treatment with lysergic acid diethylamide and psilocybin mushrooms: Findings from the Global Drug Survey 2020

Kopra, E., Ferris, J. A., Winstock, A. R. et al. · Journal of Psychopharmacology (2023)

Optimizing outcomes in psilocybin therapy: Considerations in participant evaluation and preparation

Modlin, N. L., Miller, T. M., Rucker, J. J. et al. · Journal of Affective Disorders (2023)

Pharmacokinetics and pharmacodynamics of oral psilocybin administration in healthy participants

Holze, F., Becker, A. M., Kolaczynska, K. E. et al. · Clinical Pharmacology and Therapeutics (2022)

Postpartum depression: A role for psychedelics?

Jairaj, C., Rucker, J. · Journal of Psychopharmacology (2022)

Psilocybin-Induced Mystical-Type Experiences are Related to Persisting Positive Effects: A Quantitative and Qualitative Report

McCulloch, D. E-W., Madsen, M. K., Jensen, P. S. et al. · Frontiers in Pharmacology (2022)

79 cited
Future Directions for Clinical Psilocybin Research: The Relaxed Symptom Network

Lewis-Healey, E., Laukkonen, R., Van Elk, M. · Psyarxiv (2021)

1 cited

Your Personal Research Library

Go Pro to save papers, add notes, rate studies, and organize your research into custom shelves.