A single dose of THC disrupted brain network connectivity in young adult cannabis users
In a double-blind study of 33 occasional cannabis users, a single moderate THC dose reduced functional connectivity within corticostriatal and sensory brain networks during rest.
Quick Facts
What This Study Found
THC (7.5 mg oral) reduced within-network intrinsic connectivity in corticostriatal circuits and networks associated with sensory systems, interoceptive experiences, and spatial reasoning compared to placebo. THC also reduced between-network connectivity involving anterior cingulate cortex, dorsal insula, ventral insula, and lingual gyrus regions. Network connectivity changes during THC were not related to subjective drug effects or recent cannabis use frequency.
Key Numbers
n=33 occasional cannabis users; THC 7.5 mg oral; reduced corticostriatal connectivity; reduced sensory network connectivity; reduced between-network connectivity (ACC-dorsal insula and ventral insula-lingual gyrus); no relationship to subjective effects or use frequency
How They Did This
Within-subject, double-blind, randomized study. 33 healthy occasional cannabis users received THC (7.5 mg oral) and placebo before completing resting-state fMRI during peak intoxication. Group-information-guided independent component analysis identified whole-brain networks. Within-sample t-tests assessed connectivity differences.
Why This Research Matters
This is one of few studies examining whole-brain network effects of THC rather than focusing on individual brain regions. The widespread connectivity reductions across sensory, cognitive, and reward circuits help explain the diverse behavioral and perceptual changes people experience while intoxicated.
The Bigger Picture
Understanding how THC disrupts brain networks in casual users provides baseline data for studying whether these acute disruptions become chronic with regular use. The finding that subjective experience did not predict brain changes suggests people may not perceive the extent of neural disruption THC causes.
What This Study Doesn't Tell Us
Modest sample (n=33). Only occasional cannabis users studied; heavy users might show different patterns. Single dose examined; chronic effects unknown. Resting-state fMRI captures only spontaneous brain activity, not task-related function.
Questions This Raises
- ?Do these network connectivity reductions persist beyond acute intoxication?
- ?Would chronic cannabis users show blunted or enhanced network effects?
Trust & Context
- Key Stat:
- Widespread connectivity reductions unrelated to subjective effects
- Evidence Grade:
- Double-blind within-subject RCT with whole-brain analysis provides moderate evidence of acute THC effects, limited by modest sample size and focus on occasional users only.
- Study Age:
- 2025 publication
- Original Title:
- Δ9-Tetrahydrocannabinol Alters Limbic and Frontal Functional Brain Connectomes Among Young Adult Cannabis Users.
- Published In:
- Biological psychiatry. Cognitive neuroscience and neuroimaging (2025)
- Authors:
- Anderson, Zachary, Gunn, Matthew, Jones, Emily, Ajilore, Olusola, Phan, K Luan, de Wit, Harriet, Klumpp, Heide, Calhoun, Vince, Crane, Natania A
- Database ID:
- RTHC-05938
Evidence Hierarchy
Participants are randomly assigned to treatment or placebo groups to test cause and effect.
What do these levels mean? →Frequently Asked Questions
What does reduced brain connectivity mean?
Reduced functional connectivity means brain regions that normally coordinate their activity during rest showed less synchronized activity under THC. This does not mean brain regions stopped working, but rather that their coordination was disrupted.
Did people feel the connectivity changes?
Interestingly, no. The network connectivity changes were not correlated with how intoxicated participants reported feeling, suggesting THC disrupts brain function in ways that users may not consciously perceive.
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Cite This Study
https://rethinkthc.com/research/RTHC-05938APA
Anderson, Zachary; Gunn, Matthew; Jones, Emily; Ajilore, Olusola; Phan, K Luan; de Wit, Harriet; Klumpp, Heide; Calhoun, Vince; Crane, Natania A. (2025). Δ9-Tetrahydrocannabinol Alters Limbic and Frontal Functional Brain Connectomes Among Young Adult Cannabis Users.. Biological psychiatry. Cognitive neuroscience and neuroimaging. https://doi.org/10.1016/j.bpsc.2025.09.005
MLA
Anderson, Zachary, et al. "Δ9-Tetrahydrocannabinol Alters Limbic and Frontal Functional Brain Connectomes Among Young Adult Cannabis Users.." Biological psychiatry. Cognitive neuroscience and neuroimaging, 2025. https://doi.org/10.1016/j.bpsc.2025.09.005
RethinkTHC
RethinkTHC Research Database. "Δ9-Tetrahydrocannabinol Alters Limbic and Frontal Functional..." RTHC-05938. Retrieved from https://rethinkthc.com/research/anderson-2025-9tetrahydrocannabinol-alters-limbic-and
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.