Can cannabis reduce tics in Tourette syndrome?

Tourette syndrome (TS) is characterized by motor and vocal tics driven by dysfunction in cortico-striato-thalamo-cortical circuits — circuits heavily modulated by the ECS. CB1 receptors in the basal ganglia regulate dopamine-mediated motor control, providing biological rationale. Clinical evidence: Two small RCTs exist. A 2002 German RCT (Müller-Vahl et al., n=12) found a single dose of THC significantly reduced tic severity vs. placebo on the YGTSS scale. A 2003 follow-up 6-week RCT (n=24) found THC significantly reduced tics and OCD symptoms without cognitive impairment. A 2017 observational study found medical cannabis reduced tic severity in 82% of TS patients. Limitations: all RCTs are very small; long-term safety data is absent; TS often begins in childhood, raising concerns about cannabis use in adolescents. The European Society for the Study of Tourette Syndrome considers cannabinoids a treatment option for adult TS patients who have failed standard therapies (antipsychotics, alpha-2 agonists).