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Study breakdown

Adolescent THC Exposure Disrupts Brain Myelination in Female Rats

PreclinicalModerate evidence
The takeaway

THC exposure during early-to-mid adolescence impaired myelination in the prefrontal cortex of female rats, with intensive exposure causing long-lasting effects into adulthood and increased risk-taking behavior.

Parents of adolescents, pediatricians, adolescent health researchers, and policymakers concerned about youth cannabis exposure.

What the researchers found

Both CB1 receptor blockade and THC exposure during adolescence hindered prefrontal cortex myelination in female rats. THC effects were specific to early-to-mid adolescence and, with intensive exposure, persisted into adulthood. Disrupted myelination was associated with increased risk-taking and involved the AKT/Hippo/YAP signaling pathway.

Why it matters

Adolescent brain development involves critical white matter formation. This study shows THC can disrupt this process in female rats during a specific developmental window, with potentially permanent consequences — directly relevant to rising teen cannabis use.

The numbers in context

THC impaired myelin formation only during early-to-mid adolescence. Intensive exposure protocol produced long-lasting effects persisting into adulthood. Associated with increased risk-taking behavior.

How the study worked

Preclinical study examining CB1 receptor blockade and THC exposure during adolescence in female rats, measuring prefrontal cortex myelination, behavior (risk-taking), and AKT/Hippo/YAP signaling pathway changes.

What this study cannot tell us

Female rats only — sex-specific findings may not apply to males. Rat adolescence timing differs from human. THC doses and routes may not reflect typical human use patterns.

How to read the evidence

Well-designed preclinical study identifying specific developmental vulnerability, though sex-specific (female only) and animal-model limitations apply.

When this study was published

Recent study addressing the critical question of how adolescent cannabis exposure affects ongoing brain development.

The bigger picture

White matter development continues through the mid-20s in humans. This animal evidence suggests a specific vulnerability window during early adolescence when THC exposure could permanently alter brain connectivity, with behavioral consequences like increased risk-taking.

Questions still open

  • Do male rats show the same vulnerability? Does CBD co-administration protect against THC's myelination effects? What human adolescent behaviors might correspond to the rat risk-taking findings?

Common questions

Can cannabis permanently damage a teenager's brain?
This animal study suggests intensive THC exposure during early adolescence can cause lasting disruption to brain myelination (white matter development) in females, with behavioral consequences. Human studies are needed to confirm these findings.
Why only female rats?
The researchers focused on female rats, finding clear effects. Whether males show the same vulnerability is an important unanswered question, as sex differences in cannabinoid responses are increasingly recognized.

Read the original research

Perturbations of CB1 receptor signalling during adolescence impair cortical myelination in female rats.

Pharmacological research, 216, 107758

Citation

Zamberletti, Erica; Manenti, Cristina; Prini, Pamela; Gabaglio, Marina; Grimaldi, Annalisa; Pulze, Laura; Grassi, Riccardo; Rubino, Tiziana. (2025). Perturbations of CB1 receptor signalling during adolescence impair cortical myelination in female rats.. Pharmacological research, 216, 107758. https://doi.org/10.1016/j.phrs.2025.107758

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