Clinical Takeaway
In a study of individuals at clinical high risk for psychosis, a single dose of CBD influenced the relationship between hippocampal glutamate levels and prefrontal brain activity during verbal memory tasks. This suggests CBD may work by modulating glutamate signaling in memory-related brain circuits, which are known to be disrupted in early psychosis. These findings help clarify a potential neurochemical mechanism behind CBD’s observed effects on memory function in this population.
#19 A single dose of cannabidiol modulates the relationship between hippocampal glutamate and learning-related prefrontal activation in individuals at Clinical High Risk of Psychosis.
Citation: Shi Yiling et al.. A single dose of cannabidiol modulates the relationship between hippocampal glutamate and learning-related prefrontal activation in individuals at Clinical High Risk of Psychosis.. Psychiatry research. Neuroimaging. 2026. PMID: 41337954.
Design: 5 Journal: 0 N: 1 Recency: 3 Pop: 2 Human: 1 Risk: -2
Quality Gate Alerts:
- Preclinical only
Methodological Considerations:
- Small sample — underpowered for subgroup analysis
Abstract: BACKGROUND: Cannabidiol (CBD) is being studied as a potential intervention for the people at clinical high risk for psychosis (CHR), though the mechanisms underlying its effects are not fully understood. Previous studies indicate that a single dose of CBD can normalize alterations in memory-related brain activation and modulate hippocampal glutamate levels in the early stages of psychosis. This study aimed to examine the acute effects of CBD on the relationship between hippocampal glutamate levels and brain activation during verbal memory in individuals at CHR. METHODS: A total of thirty-three participants (n = 33) at CHR were randomly assigned to receive a single 600 mg dose of CBD (CHR-CBD) or a placebo capsule (CHR-PLB). Age-matched healthy controls (HC) (n = 19) received no study drugs. Participants underwent MRI scanning while performing a verbal learning task, and proton magnetic resonance spectroscopy to measure hippocampal glutamate levels. Effect of group x hippocampal glutamate interactions on brain activation was tested. RESULTS: CHR-PLB showed positive correlation between hippocampal glutamate levels and dorsolateral prefrontal cortex (dlPFC) (Pcorr. = 0.0039) activation compared to HC during both verbal encoding and recall. Under a single dose of CBD, the glutamate-dlPFC activation relationship was negative and significantly different compared to placebo in CHR individuals (Pcorr. = 0.0001) during both verbal encoding and recall. The reversed correlation in CBD group was also observed in the parahippocampal gyrus (Pcorr. = 0.0022) and amygdala (Pcorr. = 0.0019) during verbal recall. CONCLUSIONS: These findings suggest that CBD may normalise disrupted hippocampal-prefrontal glutamatergic coupling in CHR, highlighting its potential to target the neurochemical mechanisms underlying cognitive impairment.
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