CBD restores brain network disruption caused by THC
THC disrupted the brain's default mode and salience networks, with disruption of a key region (posterior cingulate cortex) correlating with feeling "stoned," while CBD restored the salience network disruption caused by THC.
Quick Facts
What This Study Found
Both cannabis strains reduced functional connectivity in the default mode network (DMN) and salience network compared to placebo. Cannabis without CBD specifically disrupted the posterior cingulate cortex (PCC) in the DMN, and this disruption correlated with subjective feelings of being "stoned" and "high." CBD-containing cannabis restored the salience network disruption caused by THC, potentially explaining CBD's therapeutic potential for psychosis and addiction.
Key Numbers
17 volunteers. 3 treatments. Cann-CBD: 8mg THC. Cann+CBD: 8mg THC + 10mg CBD. 3 brain networks examined (default mode, executive control, salience). PCC disruption correlated with feeling "stoned."
How They Did This
Within-subjects design with 17 healthy volunteers (experienced but not regular cannabis users) receiving three treatments: cannabis with THC only (8mg THC), cannabis with THC+CBD (8mg THC + 10mg CBD), and placebo. Resting-state fMRI examined three brain networks.
Why This Research Matters
This study identifies specific brain networks affected by THC and shows that CBD can partially counteract these effects, providing a neurobiological basis for why CBD-containing cannabis may be less harmful.
The Bigger Picture
Understanding how CBD modulates THC effects at the brain network level could inform product development, harm reduction, and therapeutic applications for conditions involving salience network dysfunction like psychosis.
What This Study Doesn't Tell Us
Small sample (17). Single-dose design. Experienced users only. fMRI measures blood flow patterns as a proxy for brain activity. Cannabis strains differed in more than just CBD content.
Questions This Raises
- ?What CBD-to-THC ratio is needed to restore the salience network?
- ?Could targeted CBD supplementation reduce psychosis risk in regular THC users?
Trust & Context
- Key Stat:
- CBD restored salience network disruption by THC
- Evidence Grade:
- Well-designed within-subjects neuroimaging study with objective brain measures, but small sample and single dose.
- Study Age:
- 2019 neuroimaging study.
- Original Title:
- Dissociable effects of cannabis with and without cannabidiol on the human brain's resting-state functional connectivity.
- Published In:
- Journal of psychopharmacology (Oxford, England), 33(7), 822-830 (2019)
- Authors:
- Wall, Matthew B(11), Pope, Rebecca, Freeman, Tom P(51), Kowalczyk, Oliwia S, Demetriou, Lysia, Mokrysz, Claire, Hindocha, Chandni, Lawn, Will, Bloomfield, Michael Ap, Freeman, Abigail M, Feilding, Amanda, Nutt, David, Curran, H Valerie
- Database ID:
- RTHC-02338
Evidence Hierarchy
Participants are randomly assigned to treatment or placebo groups to test cause and effect.
What do these levels mean? →Frequently Asked Questions
How does THC affect the brain?
This fMRI study found THC disrupted the default mode network and salience network. Disruption of the posterior cingulate cortex specifically correlated with the subjective experience of feeling "stoned."
Does CBD counteract THC in the brain?
CBD restored the THC-induced disruption of the salience network, a brain system involved in detecting and responding to important stimuli. This may explain why CBD-containing cannabis is associated with lower psychosis risk.
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Cite This Study
https://rethinkthc.com/research/RTHC-02338APA
Wall, Matthew B; Pope, Rebecca; Freeman, Tom P; Kowalczyk, Oliwia S; Demetriou, Lysia; Mokrysz, Claire; Hindocha, Chandni; Lawn, Will; Bloomfield, Michael Ap; Freeman, Abigail M; Feilding, Amanda; Nutt, David; Curran, H Valerie. (2019). Dissociable effects of cannabis with and without cannabidiol on the human brain's resting-state functional connectivity.. Journal of psychopharmacology (Oxford, England), 33(7), 822-830. https://doi.org/10.1177/0269881119841568
MLA
Wall, Matthew B, et al. "Dissociable effects of cannabis with and without cannabidiol on the human brain's resting-state functional connectivity.." Journal of psychopharmacology (Oxford, 2019. https://doi.org/10.1177/0269881119841568
RethinkTHC
RethinkTHC Research Database. "Dissociable effects of cannabis with and without cannabidiol..." RTHC-02338. Retrieved from https://rethinkthc.com/research/wall-2019-dissociable-effects-of-cannabis
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.