Cannabis Reduces Tics in Tourette Syndrome: First High-Quality Trial
What Researchers Found About Tourette and Cannabis
The Study at a Glance
Published
NEJM Evidence, 2023
Researchers
Wesley Medical Research Institute / Lambert Initiative (Australia)
Study Type
Randomized Controlled TrialParticipants
22 patients · 6 weeks per period (crossover)
Key Finding
Treatment with THC and CBD reduced tics and may reduce impairment due to tics, anxiety, and obsessive-compulsive disorder, although in some participants this was associated with slowed mentation, memory lapses, and poor concentration.
Key Finding: Treatment with THC and CBD reduced tics and may reduce impairment due to tics, anxiety, and obsessive-compulsive disorder, although in some participants this was associated with slowed mentation, memory lapses, and poor concentration.
What Researchers Studied About Tourette and Cannabis
Tourette syndrome is characterized by chronic motor and vocal tics. There was preliminary evidence that cannabis products containing THC and CBD may help, and that adding CBD might improve the side effect profile.
This was a double-blind, crossover trial in participants with severe Tourette syndrome.
The study tested an oral oil containing equal amounts of THC and CBD (5 mg/mL of each) with escalating doses over 6-week treatment periods.
How This Randomized Controlled Trial Was Conducted
22 participants (8 female) with severe Tourette syndrome were enrolled.
Each participant received both active treatment and placebo in random order, with a 4-week washout period between.
The primary outcome was the total tic score on the Yale Global Tic Severity Scale (YGTSS), which ranges from 0 to 50 with higher scores indicating more severe symptoms.
Researchers also measured anxiety, depression, obsessive-compulsive symptoms, and cognitive function.
Tourette Treatment Results
The Main Results:
- 1Active treatment: tic score reduced by 8.9 points (SD 7.6)
- 2Placebo: tic score reduced by 2.5 points (SD 8.5)
- 3Significant treatment effect in statistical model (P = 0.008)
- 4Correlation found between plasma THC metabolite levels and tic improvement
- 5Most common adverse event on placebo: headache (n=7)
- 6Most common adverse event on active treatment: cognitive difficulties including slowed thinking, memory lapses, poor concentration (n=8)
By the Numbers
| Statistic | What It Means |
|---|---|
| 22 patients | Participants with severe Tourette syndrome in this crossover trial |
| -8.9 points | Reduction in tic severity score with THC/CBD treatment (vs -2.5 with placebo) |
| P = 0.008 | Statistical significance of the treatment effect in the linear mixed-effects model |
| 8/22 | Participants reporting cognitive difficulties (slowed thinking, memory, concentration) on active treatment |
Participants with severe Tourette syndrome in this crossover trial
Reduction in tic severity score with THC/CBD treatment (vs -2.5 with placebo)
Statistical significance of the treatment effect in the linear mixed-effects model
Participants reporting cognitive difficulties (slowed thinking, memory, concentration) on active treatment
What This Means for Tourette Patients
If you have severe Tourette syndrome, this trial provides encouraging evidence that a THC/CBD combination may reduce tics.
The treatment reduced tic scores significantly more than placebo (8.9 vs 2.5 point reduction). The effect was linked to blood levels of THC metabolites.
However, there is a tradeoff: about 36% of participants experienced cognitive difficulties including slowed thinking, memory lapses, and poor concentration while on the active treatment.
This is a small trial (22 participants), so more research is needed. But for people with severe tics who have not responded to other treatments, this offers a potential option worth discussing with a neurologist.
Quick Answers: Tourette and Cannabis
Direct answers based on the findings of this study:
Research Summary: Answers are based on published peer-reviewed studies and represent research findings, not medical recommendations. Individual results may vary. Always consult a healthcare provider before making treatment decisions.
Does marijuana help with Tourette syndrome?
Yes. An NEJM Evidence trial of 22 patients found THC/CBD combination significantly reduced tic severity (P = 0.008). Tic scores improved by 8.9 points on treatment vs 2.5 on placebo. However, 36% experienced cognitive side effects.
Source: Mosley et al., NEJM Evidence, 2023 (PMID: 38320199)
What are cannabis side effects for Tourette?
36% reported cognitive difficulties. In the NEJM trial, participants on THC/CBD reported slowed thinking, memory lapses, and poor concentration. This tradeoff should be considered when weighing tic reduction benefits against cognitive effects.
Source: Mosley et al., NEJM Evidence, 2023 (PMID: 38320199)
What is the best cannabis treatment for tics?
Oral oil with equal THC and CBD (5mg/mL each). The NEJM trial used escalating doses. The effect was correlated with blood THC metabolite levels, suggesting THC is the active component.
Source: Mosley et al., NEJM Evidence, 2023 (PMID: 38320199)
This is educational content, not medical advice
The research summarized here is for informational purposes only. Individual results may vary, and what works in studies may not work the same way for everyone. Always consult with a qualified healthcare provider before making changes to your treatment plan or starting medical cannabis therapy.
Important Limitations
This study has some caveats to keep in mind when interpreting the results:
- Small sample size (22 participants)
- Crossover design may have carryover effects
- Cognitive side effects occurred in 36% on active treatment
- Short treatment period (6 weeks)
- Results need confirmation in larger trials
The Bottom Line on Cannabis for Tourette
This NEJM Evidence trial provides the first high-quality evidence that THC/CBD combination reduces tics in severe Tourette syndrome (P = 0.008). Tic scores improved by 8.9 points on treatment vs 2.5 on placebo. However, 36% of participants experienced cognitive side effects including slowed thinking and memory problems. For people with severe, treatment-resistant Tourette syndrome, this may be worth discussing with a specialist.
Do You Qualify for Medical Marijuana?
If you're living with Tourette, you may qualify for a medical marijuana card. Our licensed physicians can evaluate you from home via telehealth.
Related Research & Resources
Related Research
Condition Research
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Source
Mosley PE, Webb L, Suraev A, et al. "Tetrahydrocannabinol and Cannabidiol in Tourette Syndrome" NEJM Evidence. 2023. DOI: 10.1056/EVIDoa2300012
Important Information
Not Medical Advice: This research summary is for educational purposes only. It should not be used to diagnose, treat, cure, or prevent any disease or medical condition. Always consult a qualified healthcare provider before starting or changing any treatment.
Individual Variation: Research findings represent group averages. Your individual response to cannabis may differ based on genetics, other medications, underlying conditions, and many other factors.
Last reviewed: January 25, 2026
Important Notices
Research Summary Disclaimer
This content represents our interpretation of published scientific research for educational purposes. It should not be used to make treatment decisions without consulting a qualified healthcare provider. Individual results may vary from study findings.
FDA Notice
These statements have not been evaluated by the FDA. Cannabis is not intended to diagnose, treat, cure, or prevent any disease. The FDA has not approved cannabis for any medical condition except specific prescription medications.
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Data Sources
Study information sourced from PubMed®, U.S. National Library of Medicine. Inclusion does not imply endorsement by NLM, NIH, or the federal government.
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FAQs: Cannabis for Tourette
Does cannabis help Tourette syndrome?
Yes, according to this NEJM trial. THC/CBD combination reduced tic severity scores by 8.9 points vs 2.5 with placebo in 22 patients with severe Tourette syndrome (P = 0.008). However, 36% experienced cognitive side effects.
What are the side effects of cannabis for Tourette?
36% reported cognitive difficulties. In this trial, 8 of 22 participants on active treatment reported slowed thinking, memory lapses, and poor concentration. The most common adverse event on placebo was headache.
What type of cannabis was used for Tourette in this study?
An oral oil containing equal amounts of THC and CBD (5 mg/mL of each) with escalating doses. Treatment lasted 6 weeks. The effect was correlated with blood levels of THC metabolites.