A paper co-written by researchers with the Schizophrenia Neuropharmacology Research Group at Yale (SNRGY) and published in the journal Biological Psychiatry discussed the use of cannabinoids – molecules present in marijuana -- in human laboratory studies.
Specifically, the authors discussed the effects of THC -- one of the cannabinoid molecules -- on healthy volunteers who participated in clinical studies.
The volunteers experienced effects that ranged from paranoia and perceptual alterations to impaired memory and attention. The effects were transient and usually required no intervention.
When THC was given to patients diagnosed with schizophrenia, it exacerbated their symptoms, according to the researchers.
“The importance of human laboratory studies is that they allow understanding of the effects of THC in isolation of other confounding factors like the varying amount of THC in different species of marijuana,” said Mohamed A. Sherif, MD, MSc, research fellow in psychiatry and the paper’s lead author.
The authors also discussed the use of cannabidiol, another cannabinoid molecule, in the treatment of psychosis.
More research is needed in this area, and Mohini Ranganathan, MBBS, assistant professor of psychiatry and the paper’s senior author, is conducting clinical trials to explore the advantage of using cannabidiol in psychosis.
The authors highlighted possible mechanisms by which THC produces such schizophrenia-like symptoms. These mechanisms are mediated by dopamine (the main neurotransmitter against which antipsychotic medications work), glutamate (the main excitatory neurotransmitter) and GABA (the main inhibitory neurotransmitter).
Measures of electrical activity in the brain, like EEG, where electrical activity is recorded from the scalp, can provide valuable insights into how THC produces its effect, according to the authors. Given the complexity of the interaction of THC with different neurotransmitter system, the authors pointed to the advantage of using computer models of different brain regions to improve their understanding.
SNRGY is headed by paper co-author Deepak Cyril D’Souza, MD, MBBS, professor of psychiatry. The paper’s other author was Rajiv Radhakrishnan, MD, MBBS, a fourth-year resident in the Yale Department of Psychiatry.