THC and CBD had age-dependent effects on tic-like behaviors in mice, with CBD potentially worsening tics in juveniles | Research

The takeaway

In a mouse model of Tourette syndrome, THC reduced some repetitive behaviors but caused catalepsy at higher doses, while CBD had no benefit in juveniles and actually increased head twitching in both age groups.

Neurologists treating Tourette syndrome, pediatric cannabis researchers, movement disorder specialists

CBD increased head twitch frequency in both juvenile and young adult mice

What the researchers found

THC dose-dependently reduced some DOI-induced repetitive behaviors (ear scratch > grooming > head twitch) differently in juvenile versus young adult mice. THC at 5 mg/kg caused catalepsy in controls and increased ear scratching in juveniles. CBD had no effect on DOI-induced ear scratching or grooming in juveniles and actually increased head twitching in both age groups.

Why it matters

Tourette syndrome has childhood onset and adults increasingly use medical cannabis for tics, but pediatric use is growing without age-specific evidence. This study reveals concerning age-dependent effects that could worsen symptoms in younger patients.

The numbers in context

THC potency rank in young adults: ESR > grooming > HTR; in juveniles: ESR = grooming > HTR; THC 5 mg/kg caused catalepsy in controls; CBD increased HTR frequency in both ages; CBD had no benefit for ESR or grooming in juveniles

How the study worked

Juvenile and young adult mice received DOI (2,5-dimethoxy-4-iodoamphetamine) to induce tic-like repetitive behaviors (head twitch, ear scratch, grooming). Effects of THC and CBD at various doses were compared between age groups.

What this study cannot tell us

DOI-induced repetitive behaviors are an imperfect model of Tourette syndrome tics. Mouse responses may not predict human responses. Limited dose range tested. Acute administration only; chronic effects unknown.

How to read the evidence

Systematic age comparison in a relevant animal model, but DOI model has limited translational validity for Tourette syndrome.

When this study was published

Published in 2021.

The bigger picture

The finding that CBD may increase rather than decrease tic-like behaviors challenges assumptions about its therapeutic potential in Tourette syndrome, particularly in children, and highlights the importance of age-specific pharmacological testing.

Questions still open

Could low-dose THC reduce peripheral tics without causing catalepsy? Why does CBD increase head twitching, and does this translate to tic worsening in human patients?

Common questions

Can cannabis help with Tourette syndrome tics?

THC reduced some tic-like behaviors in this mouse model but caused concerning side effects at higher doses including catalepsy. The therapeutic window was very narrow, especially in juveniles, suggesting careful dose titration would be needed.

Is CBD safe for children with tics?

In this mouse model, CBD showed no benefit for tic-like behaviors in juveniles and actually increased head twitching in both age groups. The authors caution that CBD "may not effectively treat motor tics in children and may even exacerbate tics."

Read the original research

Different responses of repetitive behaviours in juvenile and young adult mice to Δ9 -tetrahydrocannabinol and cannabidiol may affect decision making for Tourette syndrome.

British journal of pharmacology, 178(3), 614-625

View on PubMed ↗Publisher’s paper ↗

Citation

Gorberg, Victoria; McCaffery, Peter; Anavi-Goffer, Sharon. (2021). Different responses of repetitive behaviours in juvenile and young adult mice to Δ9 -tetrahydrocannabinol and cannabidiol may affect decision making for Tourette syndrome.. British journal of pharmacology, 178(3), 614-625. https://doi.org/10.1111/bph.15302