CBD altered brain activity in people with autism but not in controls
A single 600 mg dose of CBD increased brain activity in the cerebellum and fusiform gyrus, effects primarily driven by the autism group. CBD also altered connectivity between the cerebellum and striatum in participants with ASD only.
Quick Facts
What This Study Found
CBD significantly increased fractional amplitude of low-frequency fluctuations (fALFF) in the cerebellar vermis and right fusiform gyrus across all participants, but post-hoc analysis showed this was driven by the ASD group with no significant change in controls. In ASD participants only, CBD altered functional connectivity between the cerebellar vermis and subcortical/cortical targets.
Key Numbers
34 men (17 ASD, 17 controls). 600 mg CBD or placebo. CBD increased fALFF in cerebellar vermis and right fusiform gyrus (primarily in ASD). CBD altered vermal functional connectivity in ASD only.
How They Did This
Double-blind, placebo-controlled, crossover design. 34 healthy men (17 with ASD, 17 neurotypical controls) received 600 mg oral CBD or placebo. Task-free fMRI was acquired to measure brain activity and functional connectivity.
Why This Research Matters
This is one of the first studies to directly measure how CBD affects brain activity in people with ASD. The finding that CBD had a different effect in ASD versus controls suggests it may preferentially target neural circuits that are already atypical.
The Bigger Picture
The cerebellar vermis and fusiform gyrus are both regions consistently implicated in ASD. Finding that CBD selectively modulates these areas in people with autism provides a neurobiological rationale for further clinical trials.
What This Study Doesn't Tell Us
Small sample size. Single dose only. All male participants, limiting generalizability. The study measured brain activity changes, not behavioral outcomes.
Questions This Raises
- ?Do these brain changes translate to behavioral improvements?
- ?Would repeated dosing produce different or stronger effects?
- ?Would women with ASD show the same response?
Trust & Context
- Key Stat:
- CBD altered brain activity in ASD participants but not controls
- Evidence Grade:
- Moderate: randomized, double-blind, placebo-controlled crossover design, but small sample and single dose.
- Study Age:
- Published in 2019.
- Original Title:
- The effect of cannabidiol (CBD) on low-frequency activity and functional connectivity in the brain of adults with and without autism spectrum disorder (ASD).
- Published In:
- Journal of psychopharmacology (Oxford, England), 33(9), 1141-1148 (2019)
- Authors:
- Pretzsch, Charlotte M, Voinescu, Bogdan(2), Mendez, Maria A, Wichers, Robert, Ajram, Laura, Ivin, Glynis, Heasman, Martin, Williams, Steven, Murphy, Declan Gm, Daly, Eileen, McAlonan, Gráinne M
- Database ID:
- RTHC-02241
Evidence Hierarchy
Participants are randomly assigned to treatment or placebo groups to test cause and effect.
What do these levels mean? →Frequently Asked Questions
Does this prove CBD helps autism?
No. The study showed that CBD changes brain activity in regions relevant to ASD, but it did not measure whether those changes translate to behavioral improvements.
Why did CBD affect ASD brains differently than typical brains?
The endocannabinoid system may be atypical in ASD, making it more responsive to CBD modulation. The specific mechanism is not yet understood.
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Cite This Study
https://rethinkthc.com/research/RTHC-02241APA
Pretzsch, Charlotte M; Voinescu, Bogdan; Mendez, Maria A; Wichers, Robert; Ajram, Laura; Ivin, Glynis; Heasman, Martin; Williams, Steven; Murphy, Declan Gm; Daly, Eileen; McAlonan, Gráinne M. (2019). The effect of cannabidiol (CBD) on low-frequency activity and functional connectivity in the brain of adults with and without autism spectrum disorder (ASD).. Journal of psychopharmacology (Oxford, England), 33(9), 1141-1148. https://doi.org/10.1177/0269881119858306
MLA
Pretzsch, Charlotte M, et al. "The effect of cannabidiol (CBD) on low-frequency activity and functional connectivity in the brain of adults with and without autism spectrum disorder (ASD).." Journal of psychopharmacology (Oxford, 2019. https://doi.org/10.1177/0269881119858306
RethinkTHC
RethinkTHC Research Database. "The effect of cannabidiol (CBD) on low-frequency activity an..." RTHC-02241. Retrieved from https://rethinkthc.com/research/pretzsch-2019-the-effect-of-cannabidiol
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.