A pilot crossover RCT found the study protocol was feasible and acceptable for adolescents with Tourette syndrome, with three of the cannabis-treated participants rated as 'much improved' versus one on placebo.
Researchers planning cannabis trials in adolescents, clinicians treating Tourette syndrome, and families exploring treatment options for adolescent tics.
3 of 10 participants rated 'much improved' on cannabis vs 1 on placebo
What the researchers found
Seven of ten randomized adolescents completed the full protocol. Three participants were rated much improved on medicinal cannabis compared to one on placebo. The most common adverse event was dizziness (67%).
Why it matters
This is the first placebo-controlled trial of medicinal cannabis for Tourette syndrome in adolescents. While too small to prove efficacy, it demonstrates that rigorous study of cannabis in this population is achievable.
The numbers in context
10 adolescents randomized (mean age 14.8, 50% male). 7 completed the protocol. 2 discontinued due to adverse events. Dizziness in 67%. Study visit adherence: 100%. Questionnaire completion: 97.6%.
How the study worked
Phase I/II double-blind, placebo-controlled crossover trial in 10 adolescents aged 12-18 with Tourette syndrome, using THC 10mg/mL and CBD 15mg/mL in oil, with 10-week treatment phases and 4-week washout.
What this study cannot tell us
Only 10 participants, far too few for efficacy conclusions. Open-label dose titration within the crossover design. Two dropouts and one loss to follow-up further limit the small sample.
How to read the evidence
Pilot RCT designed for feasibility, not efficacy. Sample far too small for definitive conclusions about therapeutic benefit.
When this study was published
Published in 2025.
The bigger picture
Tourette syndrome often peaks during adolescence, but most cannabis research has focused on adults. Establishing feasibility of controlled trials in teens is a necessary first step toward evidence-based treatment.
Questions still open
- What sample size would a fully powered trial need? Is the 10:15 THC:CBD ratio optimal, or would different ratios work better for adolescents?
Common questions
Does this study prove cannabis works for Tourette syndrome in teenagers?
Was the treatment safe for adolescents?
Read the original research
A Pilot Randomized Placebo-Controlled Crossover Trial of Medicinal Cannabis in Adolescents with Tourette Syndrome.
Cannabis and cannabinoid research, 10(6), 702-709
Citation
Efron, Daryl; Taylor, Kaitlyn; Chan, Eunice; Payne, Jonathan M; Prakash, Chidambaram; Lee, Katherine J; Cranswick, Noel; Lin, Ping-I Daniel; Eapen, Valsamma. (2025). A Pilot Randomized Placebo-Controlled Crossover Trial of Medicinal Cannabis in Adolescents with Tourette Syndrome.. Cannabis and cannabinoid research, 10(6), 702-709. https://doi.org/10.1089/can.2024.0188
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