Possibilities of Cannabis Use in Tourette Syndrome Therapy

Introduction

Tourette syndrome (TS) is a neuropsychiatric disorder characterized by motor and vocal tics. It is often accompanied by psychiatric comorbidities such as attention deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), rage attacks, anxiety, sleep disorders, and depression. From a pathophysiological perspective, it likely involves a disruption of interaction between tonic and phasic dopaminergic signaling, resulting in impaired cortico-striato-thalamo-cortical circuits.

In the treatment of tics in TS, antipsychotics are often used; however, due to their frequent side effects and insufficient efficacy, many patients seek alternative therapies in the form of cannabis-based medicines (CBM), which are also mentioned in the American guidelines for the treatment of TS. Current data suggests that CBM are effective and well-tolerated in the treatment of TS, alleviating not only tics but also other comorbidities. However, the question remains regarding the difference in effectiveness and safety between various CBM and their routes of administration.

Study Methodology

The aim of the authors of the cited study was to expand the knowledge on the effectiveness and safety of CBM in the treatment of TS, including differences between individual preparations. The study included 98 adult outpatient patients with TS examined at the authors' facility between 2002 and 2017 who used either over-the-counter or prescribed CBM. The study had two parts. In the first part, data were collected on patients (demographic information, severity of TS, comorbidities, treatment, details of CBM use – type and amount of CBM used, duration of treatment, dosage, acute and long-term effects on tics and comorbidities, occurrence of side effects, and discontinuation of treatment). In the second part, patients themselves filled out an online questionnaire regarding their use of CBM.

Findings

Prior to examination, the study participants were prescribed an average of 5.8 medications for TS therapy. Of those using CBM for TS treatment, 71% used “street” cannabis, 37% used the synthetic cannabinoid nabiximol, 37% used the synthetic cannabinoid dronabinol, and 22% used pharmacy-prepared medical cannabis. 30% of the participants combined different CBM modalities.

The ability to evaluate the effects of CBM was possessed by 38 patients. Of these, 66% preferred medical cannabis, 18% dronabinol, 11% nabiximol, and 5% “street” cannabis. Subjective alleviation of tics was reported by 85% of these patients (by about 60%), 55% reported an improvement in comorbidities (especially OCD, ADHD, and sleep disorders), and 93% indicated an improvement in quality of life. The preferred dose and route of administration varied greatly among patients. The efficacy of CBM appeared to persist long-term.

The average duration of CBM use was 62.1 ± 73.9 months, and 33% of patients discontinued its use. At least one adverse event (AE) was reported by 55% of the analyzed patients. All these AEs were considered tolerable by the patients, most commonly dizziness, fatigue, and changes in appetite.

In comparing individual CBM, patients rated cannabis (preferably rich in tetrahydrocannabinol [THC]) as more effective than nabiximol and dronabinol. These findings were confirmed by an online survey involving 40 patients.

Conclusion

The results of the cited study provide further data supporting the efficacy and safety of CBM in treating tics and comorbidities in adult patients with Tourette syndrome. They show that patients prefer THC-rich cannabis over synthetic cannabinoids. However, it is important to consider the limitations of this study due to its retrospective design and the absence of a control group.

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Source: Milosev L. M., Psathakis N., Szejko N. et al. Treatment of Gilles de la Tourette syndrome with cannabis-based medicine: results from a retrospective analysis and online survey. Cannabis Cannabinoid Res 2019; 4 (4): 265−274, doi: 10.1089/can.2018.0050.