Neuroimaging & Brain MeasuresSafety & Risk ManagementPsilocybin

The administration of psilocybin to healthy, hallucinogen-experienced volunteers in a mock-functional magnetic resonance imaging environment: a preliminary investigation of tolerability

In a mock‑MRI environment, slow intravenous administration of up to 2 mg psilocybin in healthy, hallucinogen‑experienced volunteers produced short‑lived, typical drug effects that were psychologically and physiologically well tolerated. The findings support the feasibility of conducting fMRI studies with psilocybin under appropriate care.

Authors

  • Robin Carhart-Harris
  • David Nutt
  • Amanda Feilding

Published

Journal of Psychopharmacology
individual Study

Abstract

This study sought to assess the tolerability of intravenously administered psilocybin in healthy, hallucinogen-experienced volunteers in a mock-magnetic resonance imaging environment as a preliminary stage to a controlled investigation using functional magnetic resonance imaging to explore the effects of psilocybin on cerebral blood flow and activity. The present pilot study demonstrated that up to 2 mg of psilocybin delivered as a slow intravenous injection produces short-lived but typical drug effects that are psychologically and physiologically well tolerated. With appropriate care, this study supports the viability of functional magnetic resonance imaging work with psilocybin.

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Research Summary of 'The administration of psilocybin to healthy, hallucinogen-experienced volunteers in a mock-functional magnetic resonance imaging environment: a preliminary investigation of tolerability'

Introduction

Psilocybin is a tryptamine hallucinogen and pro-drug of psilocin that acts as a partial agonist at 5-HT2A receptors and is the active constituent of psilocybe mushrooms. After decades of restricted research following widespread recreational use and associated adverse events, clinical investigation of classical hallucinogens has resumed in recent years. Functional magnetic resonance imaging (fMRI) is a powerful tool for studying brain function, but psilocybin had not previously been administered in the MR environment and human hallucinogen research guidelines advise caution about exposing intoxicated participants to potentially anxiogenic settings. Carhart-Harris and colleagues therefore designed a preliminary tolerability study to determine whether intravenously administered psilocybin could be safely given to healthy, hallucinogen-experienced volunteers in a mock-fMRI environment. Intravenous delivery was selected because prior work suggested a rapid onset and brief duration of effects, features that are convenient for controlled fMRI experiments; the study aimed to establish whether doses up to 2 mg produced acceptable physiological and psychological responses under these conditions.

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Study Details

References (4)

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