Brain tissue from people with alcohol use disorder showed dramatically altered endocannabinoid system gene expression, with CB1 receptor genes elevated up to 125% and CB2 receptor genes reduced by half.
Addiction researchers, neuroscientists studying the endocannabinoid system, and clinicians interested in novel targets for alcohol use disorder.
What the researchers found
Individuals with AUD showed higher CNR1 expression in the prefrontal cortex (+125%) and nucleus accumbens (+78%), lower CNR2 expression in both regions (-50% and -49%), and region-specific differences in GPR55, FAAH, and MGLL expression.
Why it matters
These findings provide direct human brain evidence that chronic alcohol use is associated with widespread changes in the endocannabinoid system, suggesting this system may be a therapeutic target for alcohol addiction.
The numbers in context
CNR1: +125% in PFC, +78% in NAc. CNR2: -50% in PFC, -49% in NAc. GPR55: +19% in PFC, -51% in NAc. FAAH: -15% in PFC, +24% in NAc. MGLL: no change in PFC, -15% in NAc.
How the study worked
Postmortem case-control study comparing endocannabinoid system gene expression via qPCR in prefrontal cortex and nucleus accumbens tissue from 18 AUD patients (mean 35.5 drinking years) and 18 age-matched controls.
What this study cannot tell us
Small sample size (18 per group). Postmortem tissue cannot establish causation. Gene expression does not necessarily reflect protein levels or functional activity. Exploratory and not pre-registered.
How to read the evidence
Postmortem human brain tissue provides valuable direct evidence, but the small sample, exploratory design, and inability to determine causation limit conclusions.
When this study was published
2025 publication.
The bigger picture
Most endocannabinoid-addiction research relies on animal models. This postmortem study provides rare direct evidence from human brains, confirming that ECS changes translate to the human condition.
Questions still open
- Would medications that normalize CB1/CB2 balance reduce alcohol craving or consumption?
- Do these ECS alterations reverse with sustained abstinence?
Common questions
Why study postmortem brains?
What do the CB1 and CB2 changes mean?
Read the original research
Endocannabinoid system gene expression in mesocorticolimbic brain regions of individuals with alcohol use disorder: A descriptive study.
Addiction (Abingdon, England)
Citation
García-Gutiérrez, María Salud; Torregrosa, Abraham Bailén; Navarrete, Francisco; Aracil-Fernández, Auxiliadora; Rubio, Gabriel; Manzanares, Jorge. (2025). Endocannabinoid system gene expression in mesocorticolimbic brain regions of individuals with alcohol use disorder: A descriptive study.. Addiction (Abingdon, England). https://doi.org/10.1111/add.70293
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