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cbd and the brain

Women’s Health Research at Yale announced funding to investigate how the presumably non-intoxicating cannabis ingredient cannabidiol (CBD) affects the brain, and if it affects women and men differently. CBD use is growing in popularity exponentially, yet the safety and effectiveness of this non-regulated category of products are unknown.

Anxiety disorders are twice as prevalent among women than men, affecting one in three women over a lifetime. Such disorders are linked to higher unemployment rates, interpersonal difficulties, major depression, higher suicide rates, and substantially higher health care costs. The most commonly prescribed medications for anxiety are benzodiazepines, which are twice as likely to be prescribed to women than men and are associated with significant risk for abuse and fatal overdose when combined with opioids or alcohol.

“Many people — mostly women — are using CBD to augment or replace another medication, particularly anxiety medications,” said Dr. Sarah Lichenstein, Assistant Professor of Psychiatry and the study’s lead researcher. “But we know so little about how this substance affects our nervous system, and because research on this topic has been done mostly on men, we know almost nothing about the influence of sex. Determining the effects of a single dose of CBD in women is an essential early step toward establishing guidelines to maximize the safety and efficacy of the many products with this ingredient currently being sold with untested medical claims.”

Keywords: Cannabis (marijuana); cannabidiol; delta9-tetrahydrocannabinol; functional MRI; neuroimaging.

Background: Accumulating evidence suggests that the non-intoxicating cannabinoid compound cannabidiol (CBD) may have antipsychotic and anxiolytic properties, and thus may be a promising new agent in the treatment of psychotic and anxiety disorders. However, the neurobiological substrates underlying the potential therapeutic effects of CBD are still unclear. The aim of this systematic review is to provide a detailed and up-to-date systematic literature overview of neuroimaging studies that investigated the acute impact of CBD on human brain function. Methods: Papers published until May 2020 were included from PubMed following a comprehensive search strategy and pre-determined set of criteria for article selection. We included studies that examined the effects of CBD on brain function of healthy volunteers and individuals diagnosed with a psychiatric disorder, comprising both the effects of CBD alone as well as in direct comparison to those induced by ∆9-tetrahydrocannabinol (THC), the main psychoactive component of Cannabis. Results: One-ninety four studies were identified, of which 17 met inclusion criteria. All studies investigated the acute effects of CBD on brain function during resting state or in the context of cognitive tasks. In healthy volunteers, acute CBD enhanced fronto-striatal resting state connectivity, both compared to placebo and THC. Furthermore, CBD modulated brain activity and had opposite effects when compared to THC following task-specific patterns during various cognitive paradigms, such as emotional processing (fronto-temporal), verbal memory (fronto-striatal), response inhibition (fronto-limbic-striatal), and auditory/visual processing (temporo-occipital). In individuals at clinical high risk for psychosis and patients with established psychosis, acute CBD showed intermediate brain activity compared to placebo and healthy controls during cognitive task performance. CBD modulated resting limbic activity in subjects with anxiety and metabolite levels in patients with autism spectrum disorders. Conclusion: Neuroimaging studies have shown that acute CBD induces significant alterations in brain activity and connectivity patterns during resting state and performance of cognitive tasks in both healthy volunteers and patients with a psychiatric disorder. This included modulation of functional networks relevant for psychiatric disorders, possibly reflecting CBD’s therapeutic effects. Future studies should consider replication of findings and enlarge the inclusion of psychiatric patients, combining longer-term CBD treatment with neuroimaging assessments.

Copyright © 2021 Batalla, Bos, Postma and Bossong.

Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.