Tetrahydrocannabinol and Cannabidiol in Tourette Syndrome
Tourette syndrome is characterized by chronic motor and vocal tics. There is preliminary evidence of benefit from cannabis products containing D9-tetrahydrocannabi- nol (THC) and that coadministration of cannabidiol (CBD) improves the side-effect profile and safety.In this double-blind, crossover trial, participants with severe Tourette syndrome were randomly assigned to a 6-week treatment period with escalating doses of an oral oil containing 5 mg/ml of THC and 5 mg/ml of CBD, followed by a 6-week course of placebo, or vice versa, separated by a 4-week washout period. The primary outcome was the total tic score on the Yale Global Tic Severity Scale (YGTSS; range, 0 to 50 [higher scores indicate greater severity of symptoms]). Secondary outcomes included video-based assessment of tics, global impairment, anxiety, depression, and obsessive-compulsive symptoms. Out- comes were correlated with plasma levels of cannabinoid metabolites. A computerized cogni- tive battery was administered at the beginning and the end of each treatment period.