Rats exposed to THC around birth showed lasting changes in dopamine D2 and cannabinoid CB1 receptor gene expression in the prefrontal cortex, along with social withdrawal and cognitive impairment, but peripubertal CBD treatment reversed these abnormalities.
Neuroscience researchers, psychiatrists studying psychosis mechanisms, CBD therapy investigators
CBD reversed THC-induced social withdrawal and cognitive impairment in rats
What the researchers found
Perinatal THC exposure increased both Cnr1 (CB1) and Drd2 (D2 receptor) mRNA levels in the adult rat prefrontal cortex, with reduced DNA methylation at the Drd2 regulatory region. These changes were accompanied by social withdrawal and cognitive impairment. Peripubertal CBD treatment reversed the behavioral abnormalities. Similar DRD2 epigenetic alterations were found in human schizophrenia patients.
Why it matters
This study provides a mechanistic link between early THC exposure and schizophrenia-like changes through epigenetic modification of the dopamine system, and demonstrates that CBD may be able to reverse these alterations during a critical developmental window.
The numbers in context
Increased Cnr1 and Drd2 mRNA in adult prefrontal cortex; reduced DNA methylation at Drd2 regulatory region; lower 2-AG brain levels persisting from neonatal age to adulthood; delayed neonatal reflexes; DRD2 methylation alterations confirmed in human schizophrenia patients
How the study worked
Male rats received perinatal THC exposure and were assessed at neonatal age and adulthood for molecular (gene expression, DNA methylation via pyrosequencing, endocannabinoid levels), behavioral (social interaction, cognition), and neurological (neonatal reflexes) outcomes. Some received peripubertal CBD treatment. DRD2 methylation was also measured in a human schizophrenia cohort.
What this study cannot tell us
Male rats only. Perinatal exposure model (via mother) differs from typical human adolescent use. Small human schizophrenia sample for the translational component. CBD treatment timing (peripubertal) may not reflect realistic intervention windows.
How to read the evidence
Strong mechanistic animal study with a translational human component, but limited by male-only design and small human sample.
When this study was published
Published in 2021.
The bigger picture
The convergence of animal and human data on DRD2 epigenetic changes strengthens the case that early cannabinoid exposure can permanently alter dopamine system regulation, and that CBD intervention during adolescence might offer a preventive strategy.
Questions still open
- Could CBD treatment later in development or adulthood still reverse THC-induced epigenetic changes? Are similar DRD2 methylation patterns found in cannabis users who do not develop psychosis?
Common questions
How did THC change gene regulation?
How did CBD help?
Read the original research
Crosstalk between the transcriptional regulation of dopamine D2 and cannabinoid CB1 receptors in schizophrenia: Analyses in patients and in perinatal Δ9-tetrahydrocannabinol-exposed rats.
Pharmacological research, 164, 105357
Citation
Di Bartolomeo, Martina; Stark, Tibor; Maurel, Oriana Maria; Iannotti, Fabio Arturo; Kuchar, Martin; Ruda-Kucerova, Jana; Piscitelli, Fabiana; Laudani, Samuele; Pekarik, Vladimir; Salomone, Salvatore; Arosio, Beatrice; Mechoulam, Raphael; Maccarrone, Mauro; Drago, Filippo; Wotjak, Carsten T; Di Marzo, Vincenzo; Vismara, Matteo; Dell'Osso, Bernardo; D'Addario, Claudio; Micale, Vincenzo. (2021). Crosstalk between the transcriptional regulation of dopamine D2 and cannabinoid CB1 receptors in schizophrenia: Analyses in patients and in perinatal Δ9-tetrahydrocannabinol-exposed rats.. Pharmacological research, 164, 105357. https://doi.org/10.1016/j.phrs.2020.105357
Explore the wider topic
- How THC Affects Your Amygdala: The Brain's Threat Detector and Cannabis
- The Anandamide Connection: Your Body's Natural Bliss Molecule
- How Long for Cannabinoid Receptors to Return to Normal
- Cannabis and the Developing Brain: What Every Teenager (and Parent) Should Know
- Why Can't I Enjoy Anything Without Weed? The Science Behind It
- Dopamine Recovery After Quitting Weed: What the Science Says
- The Endocannabinoid System Explained Simply: What It Does and Why It Matters
- Your Endocannabinoid System Explained: Why Withdrawal Happens
- Your Nervous System After Quitting Weed: Fight or Flight
- Using Weed Under 18: What It Does to Your Developing Brain
- What THC Does to Your Brain: Why Withdrawal Happens
- THC and Your Prefrontal Cortex: What Cannabis Does to Your Decision-Making Brain
- Weed, Cortisol, and Stress: What Cannabis Does to Your Stress Hormones
- Weed and Memory: What the Science Says About THC and Your Hippocampus
- Weed and Motivation: Is Amotivational Syndrome Real?
- Weed and Your Nervous System: What THC Actually Does to Your Brain and Body
- How Weed Rewires Your Reward System (And How to Reset It)