Philadelphia, PA, December 3, 2015 - Several studies have demonstrated that the primary active constituent of cannabis, delta-9-tetrahydrocannabinol (?9-THC), induces transient psychosis-like effects in healthy subjects similar to those observed in schizophrenia. However, the mechanisms underlying these effects are not clear.
A new study, published in the journal Biological Psychiatry, reports that ?9-THC increases random neural activity, termed neural noise, in the brains of healthy human subjects. The findings suggest that increased neural noise may play a role in the psychosis-like effects of cannabis.
"At doses roughly equivalent to half or a single joint, ?9-THC produced psychosis-like effects and increased neural noise in humans," explained senior author Dr. Deepak Cyril D'Souza, a Professor of Psychiatry at Yale School of Medicine.
"The dose-dependent and strong positive relationship between these two findings suggest that the psychosis-like effects of cannabis may be related to neural noise which disrupts the brain's normal information processing," added first author Dr. Jose Cortes-Briones, a Postdoctoral Associate in Psychiatry at Yale School of Medicine.
The investigators studied the effects of ?9-THC on electrical brain activity in 24 human subjects who participated in a three-day study during which they received two doses of intravenous ?9-THC or placebo in a double-blind, randomized, cross-over, and counterbalanced design.
If confirmed, the link between neural noise and psychosis could shed light on the biology of some of the symptoms associated with schizophrenia.
"This interesting study suggests a commonality between the effects on the brain of the major active ingredient in marijuana and symptoms of schizophrenia," stated Dr. John Krystal, Editor of Biological Psychiatry. "The impairment of cortical function by ?9-THC could underlie some of the cognitive effects of marijuana. Not only does this finding aid our understanding of the processes underlying psychosis, it underscores an important concern in the debate surrounding medical and legalized access to marijuana."
The article is "The Psychosis-like Effects of Δ9-Tetrahydrocannabinol Are Associated with Increased Cortical Noise in Healthy Humans" by Jose A. Cortes-Briones, John D. Cahill, Patrick D. Skosnik, Daniel H. Mathalon, Ashley Williams, R. Andrew Sewell, Brian J. Roach, Judith M. Ford, Mohini Ranganathan, and Deepak Cyril D'Souza (doi: 10.1016/j.biopsych.2015.03.023). The article appears in Biological Psychiatry, Volume 78, Issue 11 (December 1, 2015), published by Elsevier.
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Notes for editors
Full text of the article is available to credentialed journalists upon request; contact Rhiannon Bugno at +1 214 648 0880 or Biol.Psych@utsouthwestern.edu. Journalists wishing to interview the authors may contact Dr. Deepak Cyril D'Souza at deepak.dsouza@yale.edu or Dr. Jose Cortes-Briones at jose.briones@yale.edu.
The authors' affiliations, and disclosures of financial and conflicts of interests are available in the article.
John H. Krystal, M.D., is Chairman of the Department of Psychiatry at the Yale School of Medicine, Chief of Psychiatry at Yale-New Haven Hospital, and a research psychiatrist at the VA Connecticut Healthcare System. His disclosures of financial and conflicts of interests are available here.
About Biological Psychiatry
Biological Psychiatry is the official journal of the Society of Biological Psychiatry, whose purpose is to promote excellence in scientific research and education in fields that investigate the nature, causes, mechanisms and treatments of disorders of thought, emotion, or behavior. In accord with this mission, this peer-reviewed, rapid-publication, international journal publishes both basic and clinical contributions from all disciplines and research areas relevant to the pathophysiology and treatment of major psychiatric disorders.
The journal publishes novel results of original research which represent an important new lead or significant impact on the field, particularly those addressing genetic and environmental risk factors, neural circuitry and neurochemistry, and important new therapeutic approaches. Reviews and commentaries that focus on topics of current research and interest are also encouraged.
Biological Psychiatry is one of the most selective and highly cited journals in the field of psychiatric neuroscience. It is ranked 6th out of 140 Psychiatry titles and 10th out of 252 Neurosciences titles in the Journal Citations Reports® published by Thomson Reuters. The 2014 Impact Factor score for Biological Psychiatry is 10.255.
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