Cannabis Reduced Tic Urges but Not Tic Severity in Small Tourette Syndrome Trial | Research

The takeaway

In a pilot crossover trial of 12 adults with Tourette syndrome, vaporized THC did not significantly reduce tic severity on video ratings but did improve premonitory urges, distress, and overall clinical impression compared to placebo.

People with Tourette syndrome considering cannabis and clinicians treating tic disorders

12 participants, crossover design

What the researchers found

THC 10% did not significantly improve the primary outcome (video-rated tic severity, MRVTRS) but was significantly better than placebo on secondary measures: premonitory urges (PUTS), subjective distress (SUDS), and clinical global impression. THC plasma levels correlated with improvements across all measures. CBD 13% alone showed no significant effects. Most participants correctly identified whether they received cannabis or placebo.

Why it matters

Tourette syndrome has limited treatment options, and many patients report cannabis helps their tics. This controlled trial provides the first rigorous evidence for vaporized cannabis, showing benefits for the subjective experience of tics even if video-rated severity did not significantly change.

The numbers in context

12 randomized, 9 completers; THC 10% significantly improved PUTS, SUDS, and CGI-I vs placebo; no significant effect on MRVTRS; THC plasma levels correlated with improvement; CBD 13% showed no significant effects

How the study worked

Double-blind, randomized crossover trial with 12 adults with Tourette syndrome (9 completers). Each participant received single vaporized doses of THC 10%, THC/CBD 9%/9%, CBD 13%, and placebo at 2-week intervals. Tic severity rated by blinded video raters. Secondary measures included premonitory urges, distress, and global impression. Plasma cannabinoid levels measured.

What this study cannot tell us

Very small sample of 9 completers limits statistical power. Single-dose design does not reflect sustained use. Most participants could tell cannabis from placebo, potentially unblinding the study. Crossover design may have carryover effects despite 2-week washout.

How to read the evidence

Randomized crossover design with blinded video ratings, but very small sample and effective unblinding limit conclusions

When this study was published

2023 study

The bigger picture

The disconnect between subjective improvement and objective tic ratings is clinically important. If cannabis reduces the urge to tic and the distress from tics without changing their frequency on video, it may still meaningfully improve quality of life for patients.

Questions still open

Would sustained THC use produce improvements on objective tic measures? Is the premonitory urge reduction the primary benefit for patients? Would a THC/CBD combination at different ratios work better? Could a larger trial confirm these preliminary findings?

Common questions

Does cannabis help Tourette syndrome tics?

In this small trial, vaporized THC did not significantly reduce tic severity on video but did significantly improve the urge to tic and overall distress. THC blood levels correlated with improvement, suggesting a dose-response relationship.

Did CBD alone help with tics?

No. CBD 13% showed no significant effects on any measure in this trial. The benefits were associated with THC, and THC plasma levels correlated with improvement.

Read the original research

A Double-Blind, Randomized, Controlled Crossover Trial of Cannabis in Adults with Tourette Syndrome.

Cannabis and cannabinoid research, 8(5), 835-845

View on PubMed ↗Publisher’s paper ↗

Citation

Abi-Jaoude, Elia; Bhikram, Tracy; Parveen, Ferdous; Levenbach, Jody; Lafreniere-Roula, Myriam; Sandor, Paul. (2023). A Double-Blind, Randomized, Controlled Crossover Trial of Cannabis in Adults with Tourette Syndrome.. Cannabis and cannabinoid research, 8(5), 835-845. https://doi.org/10.1089/can.2022.0091