Three weeks of daily CBD during adolescence produced persistent changes in adult mice — reduced anxiety and locomotion — and in mice with a schizophrenia risk gene, adolescent CBD worsened their sensitivity to THC's effects on startle responses.
Pediatric neurologists prescribing CBD, parents of children on Epidiolex, and researchers studying adolescent brain development.
What the researchers found
Adolescent CBD (30 mg/kg daily for 3 weeks) suppressed locomotion, exploration, and social behaviors while reducing anxiety-like behaviors in adult mice. In Nrg1 mutant mice (a schizophrenia susceptibility model), prior adolescent CBD exacerbated THC-induced suppression of acoustic startle response, though CBD did not alter schizophrenia-relevant behaviors.
Why it matters
CBD is increasingly used to treat adolescent conditions like epilepsy and anxiety. This study raises important safety questions about whether early-life CBD exposure has lasting brain effects that persist into adulthood — and whether it could interact with genetic vulnerability.
The numbers in context
30 mg/kg CBD daily for 3 weeks during adolescence. Testing at 5–6 months of age. Persistent effects on locomotion, exploration, social behavior, and anxiety. In Nrg1 mutants, adolescent CBD exacerbated THC-induced startle suppression.
How the study worked
Male Nrg1 TM HET mice (schizophrenia model) and wild-type controls received 30 mg/kg CBD intraperitoneally daily for 3 weeks during adolescence. At 5–6 months, they were tested for locomotion, social behavior, sensorimotor gating, cognition, and sensitivity to acute THC challenge.
What this study cannot tell us
Mouse model — behavioral tests may not translate to human experience. High dose (30 mg/kg IP) exceeds typical human dosing. Only male mice tested. Nrg1 model is one of many schizophrenia risk models. Intraperitoneal route differs from oral administration.
How to read the evidence
Preclinical study with appropriate genetic model and long follow-up period, but limited by high doses, male-only design, and intraperitoneal administration.
When this study was published
Published 2025.
The bigger picture
As CBD is increasingly prescribed to children and adolescents (e.g., Epidiolex for epilepsy), understanding its long-term developmental effects is crucial. This study suggests adolescent CBD exposure may permanently alter brain function in ways that interact with genetic predispositions.
Questions still open
- Do children taking Epidiolex show any of these persistent behavioral changes? Would lower CBD doses still produce lasting effects? Are females affected differently? Should adolescents with schizophrenia risk genes be monitored differently when prescribed CBD?
Common questions
Should teens stop taking prescribed CBD?
Did CBD worsen schizophrenia symptoms?
Read the original research
Persistent behavioural consequences of chronic adolescent cannabidiol (CBD) in a mouse model with increased susceptibility to Δ9-tetrahydrocannabinol and schizophrenia.
Progress in neuro-psychopharmacology & biological psychiatry, 138, 111306
Citation
Visini, Gabriela; Chesworth, Rose; Karl, Tim. (2025). Persistent behavioural consequences of chronic adolescent cannabidiol (CBD) in a mouse model with increased susceptibility to Δ9-tetrahydrocannabinol and schizophrenia.. Progress in neuro-psychopharmacology & biological psychiatry, 138, 111306. https://doi.org/10.1016/j.pnpbp.2025.111306
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