What topics does this cannabis study cover?

This study covers research on: THC.

Where was this research published?

Published in Psychopharmacology on August 27, 2026.

High-dose THC can mimic psychedelic effects in the right setting

Q: What did this research study find?

In this pilot, **25 mg oral *Δ9-THC*** produced a subjective experience similar to **25 mg psilocybin** under psychedelic-therapy-style conditions.

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 • August 27, 2026 • Highly Relevant

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AI Summary

This small double-blind, placebo-controlled pilot study compared oral Δ9-THC with psilocybin in the supportive environment typically used for psychedelic therapy. Four healthy adults received placebo, 25 mg psilocybin, and 25 mg Δ9-THC; two participants also received 50 mg Δ9-THC. The THC was provided either as synthetic dronabinol or a high-THC whole-plant distillate, while researchers monitored subjective experiences, cardiovascular measures, and safety.

At 25 mg, both forms of oral Δ9-THC produced subjective experiences the researchers described as similar to those produced by psilocybin. Dronabinol was mistaken for a classic hallucinogen by two participants, including one with and one without previous psychedelic experience. The findings suggest that high-dose oral THC can produce a psychedelic-like experience, particularly when expectations and the surrounding context are shaped like a psychedelic therapy session. However, the study’s very small sample means these preliminary observations cannot establish how common, predictable, or safe this effect is for cannabis users more broadly.

💡 Key Findings

In this pilot, 25 mg oral Δ9-THC produced a subjective experience similar to 25 mg psilocybin under psychedelic-therapy-style conditions.

Moderate

45%

Synthetic dronabinol was mistaken for a classic hallucinogen by two participants, including both a psychedelic-naive and a psychedelic-experienced participant.

Moderate

40%

The study suggests that set and setting may substantially influence whether oral THC is experienced as psychedelic-like.

Moderate

40%

Because the study included only four healthy adults, its findings are preliminary and cannot determine how broadly the results apply or predict individual safety.

High

80%

📄 Original Abstract

Delta-9-tetrahydrocannabinol (Δ9-THC) has been reported to evoke psychedelic-like experiences at high doses in some individuals. However, the doses of Δ9-THC that occasion such effects and the phenomenology of these experiences are poorly understood. This brief report presents preliminary findings from a pilot human laboratory study that directly compared the acute effects of Δ9-THC and psilocybin under set (expectancy) and setting (context) conditions of a typical psychedelic clinical trial. Four healthy adults (ages 31-47, 3 F) received oral administration of placebo, psilocybin (25 mg), and 25 mg Δ9-THC, and two of these participants also received 50 mg Δ9-THC, in a double-blind, placebo-controlled, within-subject crossover study. Δ9-THC was administered as either synthetic Δ9-THC (dronabinol) or a whole-plant cannabis distillate extract (89.9% Δ9-THC). Subjective effects, cardiovascular measures, and safety were monitored throughout each session. Participants were asked after each session what drug they thought they had received. 25 mg Δ9-THC in both forms yielded a subjective experience similar to 25 mg psilocybin. Dronabinol was mistaken for a classic hallucinogen by both a psychedelic-naïve and a psychedelic-experienced participant. These preliminary data suggest that a 25 mg oral dose of pure, synthetic Δ9-THC can be mistaken for a classic hallucinogen, and that oral Δ9-THC can elicit a psychedelic-like experience under set and setting conditions of a typical psychedelic clinical trial. While limited by sample size, these initial results provide insights into the comparative psychopharmacology of Δ9-THC and psilocybin as well as the potentially substantial impact of set and setting on subjective effects of psychoactive drugs. This trial was registered at ClinicalTrials.gov (NCT06772753) on January 13, 2025.

Paper Type

📄 Research

Publication

Journal: Psychopharmacology
Published: August 27, 2026
PMID: 42649324
DOI: 10.1007/s00213-026-07138-0

Authors (6)

Frederick S Barrett Department of Psychiatry and Behavioral Sciences, Johns Hopkins Center for Psychedelic and Consciousness Research, Johns Hopkins University School of Medicine, 5510 Nathan Shock Drive, Baltimore, MD, 21224, USA. fbarrett@jhmi.edu.
David Wolinsky Department of Psychiatry and Behavioral Sciences, Johns Hopkins Center for Psychedelic and Consciousness Research, Johns Hopkins University School of Medicine, 5510 Nathan Shock Drive, Baltimore, MD, 21224, USA.
Zach Daily Department of Psychiatry and Behavioral Sciences, Johns Hopkins Center for Psychedelic and Consciousness Research, Johns Hopkins University School of Medicine, 5510 Nathan Shock Drive, Baltimore, MD, 21224, USA.
Joseph Ciancio Behavioral Pharmacology Research Unit, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Kristy Arthur Department of Psychiatry and Behavioral Sciences, Johns Hopkins Center for Psychedelic and Consciousness Research, Johns Hopkins University School of Medicine, 5510 Nathan Shock Drive, Baltimore, MD, 21224, USA.
+1 more authors