# Δ9-Tetrahydrocannabinol Alters Limbic and Frontal Functional Brain Connectomes Among Young Adult Cannabis Users

> **Author:** Benjamin Caplan, MD (ABFM Board Certified, MA Lic. #240562, NPI: 1962722637)
> **Publisher:** CED Clinic (https://cedclinic.com)
> **Canonical URL:** https://cedclinic.com/research/thc-for-cannabis-use-randomized-controlled-trial/
> **Published:** 2026-10-17T10:20:17-04:00 | **Last Modified / Clinically Audited:** 2026-10-18T05:23:22-04:00
> **Clinical Summary:** Researchers studied 33 healthy young adults in their early twenties who used cannabis occasionally.

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BACKGROUND: Cannabis use among young adults has reached the highest levels ever recorded. Evidence indicates that acute Δ9-tetrahydrocannabinol (THC) disrupts brain connectivity. Few studies have examined this on a whole-brain level. We examined the effects of a single moderate dose of THC on resting-state functional brain networks among young adult cannabis users. METHODS: In a within-subject, double-blind, randomized study, 33 healthy occasional cannabis users received THC (7.5 mg, oral) and placebo before completing resting-state functional magnetic resonance imaging (rs-fMRI) during peak intoxication. Group-information–guided independent component analysis was performed on resting-state brain data to identify whole-brain networks associated with each scan. Within-samples t tests assessed for differences in intrinsic network functional connectivity and between-network functional connectivity after THC versus placebo. Additional linear models examined relationships between brain connectivity, subjective drug effects, and past-month cannabis use. RESULTS: THC reduced within-network intrinsic connectivity in corticostriatal circuits and other networks associated with sensory systems, interoceptive experiences, and spatial reasoning. THC reduced connectivity between 2 networks characterized by the anterior cingulate cortex and dorsal insula regions as well as the ventral insula and lingual gyrus, respectively. Network connectivity during THC (vs. placebo) was not related to subjective measures of drug effect or recent cannabis use. CONCLUSIONS: Our findings add to a growing literature showing that THC decreases rs-fMRI throughout the brain, impacting networks linked to the many behavioral and perceptual changes associated with THC. Future work is needed to extend these findings to clinical samples and to assess the extent to which these networks are associated with negative outcomes of chronic THC use.

 

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### Verification & Medical Governance

- **Lead Clinical Author:** Benjamin Caplan, MD
- **Credentials:** Board Certified in Family Medicine (ABFM), Former CMO Canna Care Docs (250,000+ patients supervised), Founder & CMO CED Clinic & CED Foundation, Author of *The Doctor-Approved Cannabis Handbook* (Penguin Random House).
- **Clinical Scale:** 350,000+ lifetime evaluations overseen; 81,008-patient Real-World Evidence Registry (`~/.ced_rwe_vault.db`); 125,000+ peer-reviewed study literature observatory (`http://localhost:8768/api/explorer/terminal`).
- **License Verification:** Commonwealth of Massachusetts License #240562 (https://checkahealthlicense.mass.gov/).
- **NPI Registry:** 1962722637 (https://npiregistry.cms.hhs.gov/provider-view/1962722637).
- **Ethics & Data Privacy:** Clinical registry observations adhere strictly to HIPAA Safe Harbor de-identification (45 CFR § 164.514(b)) and criteria for secondary research exemption under 45 CFR § 46.104(d)(4).