Objective: To assess the effect of Medical Cannabis (MC) on Tourette Syndrome (TS) tics and impairment.

Background: TS is a childhood onset neuropsychiatric disorder characterized by the presence of multiple motor and at least one phonic tic lasting more than one year. Several randomized controlled and retrospective trials demonstrated MC may suppress tics and associated behavioral problems. Interrelation of the endocannabinoid system in the cortico-striato-thalamo-cortical circuit, limbic system and insula all play a major role in the pathophysiology of TS may explain the observed mitigation of symptoms.

Method: An open label prospective study of patients from the TS clinic at the Tel-Aviv Sourasky Medical Center, with approved MC licensing from the ministry of health. Type of the MC and mode of use were recommended by the treating neurologist.  Overall follow-up period was 3 months. Patients were assessed at one and 3-month following treatment initiation for treatment efficacy, tolerability and side effects.

Results: 18 patients entered the study, age (mean± standard error) 31.11±2.17, 12 males. Baseline Yale Global Tic Severity Scale (YGTSS)-severity (range 0-50) 25.27±2.47, YGTSS-impairment (range 0-50) 35.00±2.58. Three patients did not reach end of follow up. Average dose of MC after 3 months (grams/month) 18.00±1.33, %THC 12.33±1.24, %CBD 3.61±0.83, mode of administration: cigarettes (80%), vapor (13%), oil (13%), frequency of use 2.93±0.34 (per day), response of tics to treatment (Likert scale 1-7) 5.5±0.35, percent subjective reduction of tics (0-100%) 53.93±6.78. Average reduction of YGTSS-total for naïve users after three months of treatment was 37.07%. Major side effects include dry mouth (66.67%), fatigue (53.33%) and dizziness (46.67%). Three patients suffered from anxiety at treatment initiation: one stopped treatment because of worsening of obsessive-compulsive disorder, one from panic attack which resolved after THC dose reduction and one from anxiety which resolved with no treatment modification. Five patients reported cognitive side effects regarding (one patient for each) time perception, visuospatial disorientation, confusion, slow processing speed and attention.

Conclusion: Preliminary results show that MC has good efficacy and good tolerability. The most common mode of use is smoking with a high THC percentage. Cognitive and psychiatric side effects have to be monitored and addressed.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/positive-effect-of-medical-cannabis-in-adults-with-tourette-syndrome/