Cannabis-Based Medicine Reduced Tic Severity in Tourette Syndrome

Cannabis-based medicine produced a significant reduction in Yale Global Tic Severity Scale scores (MD = -23.71, p = 0.02) and Premonitory Urge for Tics Scale scores (MD = -5.36, p = 0.0007). There was no significant effect on obsessive-compulsive symptoms as measured by the Y-BOCS (p = 0.06).

Systematic review and meta-analysis searching PubMed, Cochrane, Scopus, and Web of Science through February 2024. Nine studies were included in the systematic review and three in the meta-analysis, involving 401 adult patients with Tourette syndrome.

Tourette syndrome has limited treatment options, and existing medications (mainly neuroleptics) come with significant side effects. Cannabis-based medicine represents a potential alternative, and this is the first meta-analysis to pool the available evidence on its effectiveness for tics.

The endocannabinoid system has known interactions with the basal ganglia circuits involved in tic generation. These results, while preliminary, provide a biological rationale for further investigation of cannabinoid therapies in movement disorders beyond just Tourette syndrome.

Only 3 of 9 studies could be pooled for meta-analysis, reflecting small and heterogeneous literature. Total sample was only 401 patients. The confidence interval for the YGTSS reduction was wide (-43.86 to -3.55), indicating high uncertainty. Most studies lacked placebo controls.