A small placebo-controlled trial of medicinal cannabis for Tourette tics in teenagers
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.
Quick Facts
What This Study 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%).
Key Numbers
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 They Did This
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.
Why This Research 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 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.
What This Study Doesn't 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.
Questions This Raises
- ?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?
Trust & Context
- Key Stat:
- 3 of 10 participants rated 'much improved' on cannabis vs 1 on placebo
- Evidence Grade:
- Pilot RCT designed for feasibility, not efficacy. Sample far too small for definitive conclusions about therapeutic benefit.
- Study Age:
- Published in 2025.
- Original Title:
- A Pilot Randomized Placebo-Controlled Crossover Trial of Medicinal Cannabis in Adolescents with Tourette Syndrome.
- Published In:
- Cannabis and cannabinoid research, 10(6), 702-709 (2025)
- Authors:
- Efron, Daryl(6), Taylor, Kaitlyn(4), Chan, Eunice(2), Payne, Jonathan M, Prakash, Chidambaram, Lee, Katherine J, Cranswick, Noel, Lin, Ping-I Daniel, Eapen, Valsamma
- Database ID:
- RTHC-06390
Evidence Hierarchy
Participants are randomly assigned to treatment or placebo groups to test cause and effect.
What do these levels mean? →Frequently Asked Questions
Does this study prove cannabis works for Tourette syndrome in teenagers?
No. This was a feasibility pilot with only 10 participants. It showed that conducting rigorous cannabis trials in teens with Tourette is possible, but a much larger study is needed to determine efficacy.
Was the treatment safe for adolescents?
Dizziness was common (67%), and two participants dropped out due to adverse events. There were no serious adverse events. The overall safety profile was considered acceptable for a pilot study.
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Cite This Study
https://rethinkthc.com/research/RTHC-06390APA
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
MLA
Efron, Daryl, et al. "A Pilot Randomized Placebo-Controlled Crossover Trial of Medicinal Cannabis in Adolescents with Tourette Syndrome.." Cannabis and cannabinoid research, 2025. https://doi.org/10.1089/can.2024.0188
RethinkTHC
RethinkTHC Research Database. "A Pilot Randomized Placebo-Controlled Crossover Trial of Med..." RTHC-06390. Retrieved from https://rethinkthc.com/research/efron-2025-a-pilot-randomized-placebocontrolled
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.