Δ9-tetrahydrocannabinol (THC) is effective in the treatment of tics in Tourette syndrome: A 6-week randomized trial.

Studied whether THC is effective and safe in reducing tics in Tourette syndrome (TS). In this randomized, double-blind, placebo-controlled study, 24 patients (aged 18-68 yrs) with TS were treated over a 6-wk period with up to 10 mg/day of THC. Tics were rated at 6 visits (visit 1, baseline; visits 2-4, during treatment period; visits 5-6, after withdrawal of medication) using the Tourette Syndrome Clinical Global Impressions scale (TS-CGI), the Shapiro Tourette-Syndrome Severity Scale (STSSS), the Yale Global Tic Severity Scale (YGTSS), the self-rated Tourette Syndrome Symptom List (TSSL), and a videotape-based rating scale. Seven patients dropped out of the study or had to be excluded, but only 1 due to side effects. Using the TS-CGI, STSSS, YGTSS, and video rating scale, there was a significant difference or a trend toward a significant difference between THE and placebo groups at visits 2, 3, and/or 4. Using the TSSL at 10 treatment days (between days 16 and 41) there was a significant difference between both groups. ANOVA as well demonstrated a significant difference. No serious adverse effects occurred. Results provide evidence that THC is effective and safe in the treatment of tics. Thus the central cannabinoid receptor system might play a role in TS pathology. (PsycInfo Database Record (c) 2021 APA, all rights reserved)