Growing evidence supports cannabis-based medicine for Tourette syndrome tics and comorbidities | Research

The takeaway

A review of cannabis-based treatments for Tourette syndrome found growing evidence of efficacy for tics and psychiatric comorbidities, with two small RCTs demonstrating THC safety and efficacy, though larger trials are still needed.

Patients with Tourette syndrome dissatisfied with current treatments, neurologists, and researchers studying tic disorders.

Two RCTs showed THC safe and effective for tics

What the researchers found

Two small RCTs using THC (dronabinol) demonstrated safety and efficacy for tic treatment in Tourette syndrome. However, a trial of the endocannabinoid modulator Lu AG06466 failed. Current guidelines classify cannabis-based treatment as experimental for treatment-resistant patients.

Why it matters

Tourette syndrome has limited treatment options, and many patients experience intolerable side effects from antipsychotics. Cannabis-based treatments represent a potential alternative for treatment-resistant patients.

The numbers in context

Two published RCTs using THC/dronabinol showed safety and efficacy. One RCT of Lu AG06466 (endocannabinoid modulator) was negative. Both AAN and ESSTS guidelines classify cannabis treatment as experimental. Larger RCT (CANNA-TICS) is ongoing.

How the study worked

Two reviewers searched PubMed for studies on cannabis/cannabinoid treatment of Tourette syndrome. Included case reports, case series, open uncontrolled studies, and RCTs. Reviewed evidence for tic reduction and comorbidity management.

What this study cannot tell us

Majority of evidence is from case reports and uncontrolled studies. The two positive RCTs were small. Cannabis-based treatment remains experimental by guideline standards. The failed endocannabinoid modulator trial complicates the picture.

How to read the evidence

Moderate: includes two positive RCTs, but most evidence is from lower-quality study designs and sample sizes are small.

When this study was published

Published in 2022.

The bigger picture

While most evidence comes from case reports and small studies, the two positive RCTs and the ongoing CANNA-TICS trial suggest cannabis-based medicine may eventually join the standard treatment toolkit for Tourette syndrome.

Questions still open

Will the CANNA-TICS trial confirm earlier positive findings? Why did the endocannabinoid modulator fail while THC succeeded? Would CBD alone or CBD:THC combinations be more effective or better tolerated?

Common questions

Is cannabis approved for Tourette syndrome?

No. Both the American Academy of Neurology and the European Society for the Study of Tourette Syndrome classify cannabis-based treatment as experimental, recommended only for treatment-resistant patients.

What form of cannabis showed benefit?

The two positive RCTs used THC (dronabinol). Other forms (whole-plant, nabiximols) have been studied in smaller, uncontrolled settings with generally positive results.

Did cannabis help with more than just tics?

Yes. Evidence suggests cannabis-based medicine may also improve psychiatric comorbidities commonly seen in Tourette syndrome, such as OCD and anxiety, though this evidence is less robust.

Read the original research

Cannabis-based medicine in treatment of patients with Gilles de la Tourette syndrome.

Neurologia i neurochirurgia polska, 56(1), 28-38

View on PubMed ↗Publisher’s paper ↗

Citation

Szejko, Natalia; Saramak, Kamila; Lombroso, Adam; Müller-Vahl, Kirsten. (2022). Cannabis-based medicine in treatment of patients with Gilles de la Tourette syndrome.. Neurologia i neurochirurgia polska, 56(1), 28-38. https://doi.org/10.5603/PJNNS.a2021.0081