A new clinical trial has found that a combination of tetrahydrocannabinol (THC) and cannabidiol (CBD) may effectively reduce tics and associated symptoms in patients with severe Tourette syndrome.
The double-blind, placebo-controlled crossover study was conducted by researchers in Australia. It involved 22 participants with severe Tourette syndrome randomly assigned to receive either an escalating dose of an oral cannabis oil containing equal parts THC and CBD, or a placebo, over a 6-week period.
Using the Yale Global Tic Severity Scale (YGTSS) as the primary outcome measure, the researchers observed a significantly greater reduction in total tic scores for those in the THC/CBD treatment group compared to placebo.
"In a linear mixed-effects model, there was a significant interaction showing a greater decrease, or improvement, in tics under the active THC/CBD treatment versus placebo,"
Secondary outcomes like anxiety, obsessive-compulsive symptoms and global impairment also tended to improve with the cannabis treatment, though the cannabinoids were associated with some cognitive side effects like slowed thinking and memory issues in a subset of participants.
Importantly, the therapeutic effects on tic reduction correlated with circulating blood levels of THC's primary metabolite 11-hydroxy-THC, suggesting the improvements were directly mediated by cannabinoid activity.
"In severe Tourette syndrome, treatment with THC and CBD reduced tics and may reduce impairment due to tics, anxiety, and obsessive-compulsive disorder,"
The promising results add to the growing body of evidence supporting cannabinoid therapeutics for treating Tourette's and tic disorders. Further research is still needed on optimal dosing, ratios of THC to CBD, and identifying patients most likely to benefit versus experience side effects.
Full study - https://evidence.nejm.org/doi/full/10.1056/EVIDoa2300012