Single dose of CBD increased blood flow to the hippocampus in healthy adults
A 600mg dose of CBD significantly increased cerebral blood flow to the hippocampus, a key memory-processing region, in a small crossover trial of 15 healthy participants.
Quick Facts
What This Study Found
CBD increased cerebral blood flow in the hippocampus by an average of 15 mL/100g/min compared to placebo (Cohen's d = 0.75, p = 0.004). Greater CBD-induced increases in orbitofrontal CBF correlated with faster reaction times on a working memory task (r = -0.73, p = 0.005).
Key Numbers
Hippocampal CBF increase: 15.00 mL/100g/min (95% CI: 5.78-24.21), Cohen's d = 0.75. Orbitofrontal CBF and 2-back reaction time correlation: r = -0.73, p = 0.005.
How They Did This
Randomized, crossover, double-blind design with 15 healthy participants receiving 600mg oral CBD or placebo on separate days. Cerebral blood flow measured at rest using arterial spin labelling MRI 3 hours after ingestion. Memory assessed via digit span, n-back, and prose recall tasks.
Why This Research Matters
The hippocampus is central to memory formation, and showing that CBD increases blood flow there suggests a potential mechanism for CBD's therapeutic effects in conditions involving memory dysfunction.
The Bigger Picture
These findings point to a possible mechanism by which CBD could influence conditions associated with altered memory processing, including Alzheimer's disease, PTSD, and schizophrenia.
What This Study Doesn't Tell Us
Very small sample (15 participants); single-dose design; no differences in actual memory task performance were detected; only healthy participants studied.
Questions This Raises
- ?Would repeated CBD dosing produce sustained changes in hippocampal blood flow?
- ?Would similar effects appear in people with memory-related conditions?
Trust & Context
- Key Stat:
- CBD increased hippocampal blood flow with a medium-to-large effect size (d = 0.75)
- Evidence Grade:
- Small randomized crossover trial (n=15) with a single dose in healthy volunteers.
- Study Age:
- Published in 2020.
- Original Title:
- The effects of acute cannabidiol on cerebral blood flow and its relationship to memory: An arterial spin labelling magnetic resonance imaging study.
- Published In:
- Journal of psychopharmacology (Oxford, England), 34(9), 981-989 (2020)
- Authors:
- Bloomfield, Michael A P(7), Green, Sebastian F(3), Hindocha, Chandni(13), Yamamori, Yumeya, Yim, Jocelyn Lok Ling, Jones, Augustus P M, Walker, Hannah R, Tokarczuk, Pawel, Statton, Ben, Howes, Oliver D, Curran, H Valerie, Freeman, Tom P
- Database ID:
- RTHC-02430
Evidence Hierarchy
Participants are randomly assigned to treatment or placebo groups to test cause and effect.
What do these levels mean? →Frequently Asked Questions
Did CBD actually improve memory in this study?
No significant differences in memory task performance were found between CBD and placebo sessions. However, greater blood flow increases in one brain region did correlate with faster reaction times on a working memory task.
Why is increased hippocampal blood flow potentially important?
The hippocampus plays a central role in forming new memories. Several conditions involving memory dysfunction, such as Alzheimer's disease and PTSD, show altered hippocampal function, so increased blood flow there could be therapeutically relevant.
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Cite This Study
https://rethinkthc.com/research/RTHC-02430APA
Bloomfield, Michael A P; Green, Sebastian F; Hindocha, Chandni; Yamamori, Yumeya; Yim, Jocelyn Lok Ling; Jones, Augustus P M; Walker, Hannah R; Tokarczuk, Pawel; Statton, Ben; Howes, Oliver D; Curran, H Valerie; Freeman, Tom P. (2020). The effects of acute cannabidiol on cerebral blood flow and its relationship to memory: An arterial spin labelling magnetic resonance imaging study.. Journal of psychopharmacology (Oxford, England), 34(9), 981-989. https://doi.org/10.1177/0269881120936419
MLA
Bloomfield, Michael A P, et al. "The effects of acute cannabidiol on cerebral blood flow and its relationship to memory: An arterial spin labelling magnetic resonance imaging study.." Journal of psychopharmacology (Oxford, 2020. https://doi.org/10.1177/0269881120936419
RethinkTHC
RethinkTHC Research Database. "The effects of acute cannabidiol on cerebral blood flow and ..." RTHC-02430. Retrieved from https://rethinkthc.com/research/bloomfield-2020-the-effects-of-acute
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.