Scientists in Tel Aviv, Israel have released the results of a small study into the viability of treating Tourette syndrome with cannabis. The open-label clinical trial was to determine the effectiveness and tolerability of medicinal cannabis treatment on adult patients who live with Gilles de la Tourette syndrome (GTS).
GTS is a childhood-onset neuropsychiatric disorder that is characterised by multiple motor tics and at least one phonic tic that continues for at least one year. GTS is considered in the medical community to be fairly common, with between 0.3-0.8% of children being diagnosed. Tics will naturally change in severity and are also vulnerable to external environmental influences such as stress, anxiety and fatigue. Other psychiatric disorders that have been strongly linked to GTS include ADHD, OCD, depression, anxiety, sleep disorders and rage attacks. Current treatment includes behavioural therapy such as CBIT, which is considered to be effective, and medications such as antipsychotic drugs which are known to produce serious side effects in some patients.
The 18 participants in the study decided which way they would like to consume their cannabis treatment, after advice from the researchers and clinicians; through smoking or vaping of dried flower, or a digested oil extract. This decision was made before the study commenced, with 80% of participants choosing the smoking method. The cannabis used contained 10% THC and 2% CBD, this was set for the duration of the trial. Clinicians advised participants to evaluate the effects the medication was having on their bodies before increasing the dose from one drop of oil or one inhalation of their vape or cannabis cigarette. After treatment commenced, the participants were assessed at week 4 and week 8 for the efficacy of the treatment, tolerability of the medication, and any side effects they may have experienced.
From the initial 18 participants that entered the study, 15 finished with 3 participants not making it to the end of the follow-up period for various medical and psychiatric reasons. Researchers used the Yale Global Tic Severity Scale, (YGTSS) to assess the participant’s tics. After 4 weeks of treatment, researchers observed a substantial 32.8% reduction in tics, this rose significantly to 38% once the 12-week treatment had been completed. Using a tool called a Likert scale, researchers measured and analysed participants’ experience of using cannabis and its influence on their tics; the results were overwhelmingly positive, showing a 54% improvement from pre-trial scores.
Various side-effects from the medicine were reported, with the most common being; dry mouth 66%, fatigue 53% and dizziness, 46%. Less common were reports of worsening of OCD symptoms, panic attacks and anxiety.
The researchers concluded that medicinal cannabis treatment for GTS “demonstrates good efficacy and tolerability in adult patients. From our data, it is suggested that MC [medical cannabis] might be a treatment option for resistant TS patients, and MC has a significant effect on tics, premonitory urges, and patients’ overall quality of life”. They continue their conclusion with, “predilection for smoking, rather than using oil drops, requires further comparative studies to evaluate the efficacy of each. Cognitive and psychiatric side effects have to be monitored and addressed.”
The results showed promise for the treatment of GTS using cannabis medicine, but due to the small cohort and limitations in recording and measuring the results, and the lack of insight into the past cannabis use of the participants, more research must be undertaken. However, these results can be added to not only the ample real-world anecdotal evidence available but also to results from bigger studies done in the past including from Mueller-Vahl et al who published two consecutive RCTs in 2002-2003 that demonstrated the safety and efficacy of the THC compound dronabinol in the treatment of GTS.