A patient with treatment-resistant Tourette syndrome showed no improvement with antipsychotics or pure THC, but a combination of 10 mg THC with 20 mg CBD produced rapid, significant improvement in tic severity.
People with Tourette syndrome, neurologists, and researchers studying cannabinoid-based treatments.
THC alone failed; THC + CBD produced rapid tic improvement
What the researchers found
Standard antipsychotic treatments (risperidone, aripiprazole) and pure delta-9-THC had no significant effect on tics. When the patient received a daily combination of 10 mg THC and 20 mg CBD, there was a rapid and highly significant improvement on the Yale Global Tic Severity Scale.
Why it matters
This case suggests that the combination of THC and CBD may be more effective than either alone for Tourette syndrome, and that CBD may be the key therapeutic component.
The numbers in context
Daily dose: 10 mg THC + 20 mg CBD. Outcome: rapid, highly significant improvement on the Yale Global Tic Severity Scale. Prior treatments (risperidone, aripiprazole, pure THC) all failed.
How the study worked
Single case report of a female patient with treatment-resistant Tourette syndrome who sequentially tried multiple treatments.
What this study cannot tell us
Single case report; results may not generalize. No blinding or placebo control. The sequential nature of treatments makes it hard to rule out time-related or placebo effects.
How to read the evidence
Preliminary: single uncontrolled case report.
When this study was published
Published in 2019.
The bigger picture
The concept that cannabis components work better together than alone (sometimes called the entourage effect) has been debated. This case adds a data point suggesting CBD may enhance or enable the therapeutic effects of THC in at least some conditions.
Questions still open
- Would CBD alone have produced the same improvement? What is the optimal THC:CBD ratio for Tourette syndrome? Can these findings be replicated in a controlled trial?
Common questions
What is the Yale Global Tic Severity Scale?
Why might CBD help when THC alone didn't?
Read the original research
Pure delta-9-tetrahydrocannabinol and its combination with cannabidiol in treatment-resistant Tourette syndrome: A case report.
International journal of psychiatry in medicine, 54(2), 150-156
Citation
Pichler, Eva-Maria; Kawohl, Wolfram; Seifritz, Erich; Roser, Patrik. (2019). Pure delta-9-tetrahydrocannabinol and its combination with cannabidiol in treatment-resistant Tourette syndrome: A case report.. International journal of psychiatry in medicine, 54(2), 150-156. https://doi.org/10.1177/0091217418791455
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