Brain imaging studies show altered cannabinoid signaling across multiple psychiatric disorders
PET imaging studies found altered CB1 receptor binding in cannabis use disorder, alcohol use disorder, schizophrenia, PTSD, and eating disorders, with cannabis users showing decreased binding that normalizes with abstinence.
Quick Facts
What This Study Found
Cannabis users consistently had decreased CB1 receptor binding compared to controls, normalizing after short abstinence periods. Alcohol use disorder and schizophrenia showed inconsistent results (some studies finding increased, others decreased binding). Preliminary evidence of altered CB1 binding was also found in anorexia nervosa and PTSD.
Key Numbers
Five psychiatric disorders studied via PET: cannabis use disorder, alcohol use disorder, schizophrenia, PTSD, eating disorders. Cannabis users: consistent CB1 decrease. Alcohol/schizophrenia: inconsistent results.
How They Did This
Comprehensive review of PET imaging studies comparing endocannabinoid signaling (primarily CB1 receptor binding) between psychiatric patients and healthy controls across five disorder categories.
Why This Research Matters
This review consolidates brain imaging evidence that the endocannabinoid system is disrupted across a wide range of psychiatric disorders, not just cannabis-related conditions. This supports the endocannabinoid system as a transdiagnostic treatment target.
The Bigger Picture
The normalization of CB1 binding after cannabis abstinence suggests the brain's endocannabinoid system can recover, which is an encouraging finding for people trying to quit.
What This Study Doesn't Tell Us
Most studies used CB1 radiotracers, limiting assessment of other endocannabinoid components. Small sample sizes in many PET studies. Inconsistent findings in some disorders make it hard to draw firm conclusions.
Questions This Raises
- ?Would targeting the endocannabinoid system with medications benefit multiple psychiatric disorders?
- ?How long does it take for CB1 binding to fully normalize after cannabis cessation?
- ?Could PET imaging predict treatment response?
Trust & Context
- Key Stat:
- Cannabis-related CB1 decreases normalized with short-term abstinence
- Evidence Grade:
- Moderate: comprehensive systematic review of PET imaging studies, limited by small sample sizes in original studies.
- Study Age:
- Published in 2019.
- Original Title:
- Endocannabinoid signaling in psychiatric disorders: a review of positron emission tomography studies.
- Published In:
- Acta pharmacologica Sinica, 40(3), 342-350 (2019)
- Authors:
- Sloan, Matthew E(7), Grant, Caroline W, Gowin, Joshua L(4), Ramchandani, Vijay A, Le Foll, Bernard
- Database ID:
- RTHC-02297
Evidence Hierarchy
Analyzes all available research on a topic using a structured method.
What do these levels mean? →Frequently Asked Questions
What does decreased CB1 binding mean?
It means the brain has fewer available CB1 cannabinoid receptors (likely downregulated from chronic cannabis exposure). This may reduce the brain's ability to respond to its own endocannabinoid signals.
How quickly does the brain recover after quitting cannabis?
The reviewed studies found CB1 binding began normalizing after relatively short abstinence periods, though the exact timeline varied. This is encouraging for recovery potential.
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Cite This Study
https://rethinkthc.com/research/RTHC-02297APA
Sloan, Matthew E; Grant, Caroline W; Gowin, Joshua L; Ramchandani, Vijay A; Le Foll, Bernard. (2019). Endocannabinoid signaling in psychiatric disorders: a review of positron emission tomography studies.. Acta pharmacologica Sinica, 40(3), 342-350. https://doi.org/10.1038/s41401-018-0081-z
MLA
Sloan, Matthew E, et al. "Endocannabinoid signaling in psychiatric disorders: a review of positron emission tomography studies.." Acta pharmacologica Sinica, 2019. https://doi.org/10.1038/s41401-018-0081-z
RethinkTHC
RethinkTHC Research Database. "Endocannabinoid signaling in psychiatric disorders: a review..." RTHC-02297. Retrieved from https://rethinkthc.com/research/sloan-2019-endocannabinoid-signaling-in-psychiatric
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.