Cannabinoids show promise for Tourette syndrome but rigorous evidence is nearly nonexistent | Research

The takeaway

Despite a strong biological rationale and widespread anecdotal reports of tic improvement, only two small randomized trials of THC for Tourette syndrome exist, leaving efficacy and safety largely unknown.

Tourette syndrome patients and families, neurologists, and researchers planning cannabinoid clinical trials.

Only 2 small trials exist

What the researchers found

There is a strong biological rationale for cannabinoid effects on tics, and many patients report improvement with cannabis. However, only two small randomized, placebo-controlled trials of THC have been published, and these merely suggested possible benefits. Trials of other cannabinoid agents are ongoing. The authors recommend restricting clinical use to adults given developmental risks.

Why it matters

Tourette syndrome has limited pharmacological options, and many patients report cannabis helps their tics. But the evidence base consists of just two small trials, creating a gap between patient experience and clinical guidance.

The numbers in context

Only 2 small randomized controlled trials published (both testing THC). Multiple anecdotal case reports and series describe tic improvement. Additional trials of cannabinoid system agents are ongoing.

How the study worked

Comprehensive literature search of PubMed for randomized controlled trials and clinical trials of cannabis-derived medications in Tourette syndrome. Extracted population, intervention, safety, and outcome data.

What this study cannot tell us

Extremely limited trial data. Only THC has been tested in RCTs, not CBD or other cannabinoids. Safety profile is largely unknown in this population. Developmental effects of cannabinoids in children with Tourette syndrome are a concern.

How to read the evidence

Rated preliminary because the entire evidence base consists of two small RCTs, anecdotal reports, and biological rationale.

When this study was published

Published in 2019. Additional clinical trials for cannabinoids in Tourette syndrome may have reported results since.

The bigger picture

Tourette syndrome is a textbook case of the cannabinoid evidence gap: strong biological plausibility, consistent patient reports, but almost no rigorous trial data. The field needs larger trials before clinical recommendations can be made.

Questions still open

Will ongoing trials confirm the anecdotal benefits? Is THC, CBD, or another cannabinoid most effective for tics? Can cannabinoid treatments be developed that are safe enough for the pediatric Tourette population?

Common questions

Does cannabis help Tourette syndrome tics?

Many patients report it does, and there is a plausible biological mechanism. However, only two small clinical trials have been conducted, and they merely suggested possible benefit without definitive proof.

Is it safe for children with Tourette syndrome?

The review recommends restricting cannabinoid treatments to adults due to uncertain efficacy and potential developmental adverse effects in children.

What cannabinoid has been tested?

Only THC has been tested in randomized controlled trials for Tourette syndrome. Trials of other cannabinoid system agents are ongoing.

Read the original research

The Potential of Cannabinoid-Based Treatments in Tourette Syndrome.

CNS drugs, 33(5), 417-430

View on PubMed ↗Publisher’s paper ↗

Citation

Artukoglu, Bekir B; Bloch, Michael H. (2019). The Potential of Cannabinoid-Based Treatments in Tourette Syndrome.. CNS drugs, 33(5), 417-430. https://doi.org/10.1007/s40263-019-00627-1