The Effects of Acute Δ9-Tetrahydrocannabinol on Striatal Glutamatergic Function: A Proton Magnetic Resonance Spectroscopy Study

Michael A.P. Bloomfield, Katherine Petrilli, Rachel Lees, Chandni Hindocha, Katherine Beck, Ryan J. Turner, Ellis Chika Onwordi, Neil Rane, David J. Lythgoe, James M. Stone, H. Valerie Curran, Oliver D. Howes, Tom P. Freeman

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Background: Cannabis and its main psychoactive component, Δ9-tetrahydrocannabinol (THC), can elicit transient psychotic symptoms. A key candidate biological mechanism of how THC induces psychotic symptoms is the modulation of glutamate in the brain. We sought to investigate the effects of acute THC administration on striatal glutamate levels and its relationship to the induction of psychotic symptoms. Methods: We used proton magnetic resonance spectroscopy to measure glutamate levels in the striatum in 20 healthy participants after THC (15 mg, oral) and matched placebo administration in a randomized, double-blind, placebo-controlled design. Psychotic symptoms were measured using the Psychotomimetic States Inventory. Results: We found that THC administration did not significantly change glutamate (glutamate plus glutamine relative to creatine) concentration in the striatum (p =.58; scaled Jeffreys-Zellner-Siow Bayes factor = 4.29). THC increased psychotic symptoms, but the severity of these symptoms was not correlated with striatal glutamate levels. Conclusions: These findings suggest that oral administration of 15 mg of THC does not result in altered striatal glutamate levels. Further work is needed to clarify the effects of THC on striatal glutamate.

Original languageEnglish
Pages (from-to)660-667
Number of pages8
JournalBiological Psychiatry: Cognitive Neuroscience and Neuroimaging
Volume6
Issue number6
Early online date4 Jun 2021
DOIs
Publication statusPublished - 30 Jun 2021

Keywords

  • Cannabis
  • Glutamate
  • MRS
  • Psychosis
  • Striatum
  • Tetrahydrocannabinol

ASJC Scopus subject areas

  • Biological Psychiatry
  • Cognitive Neuroscience
  • Clinical Neurology
  • Radiology Nuclear Medicine and imaging

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