Tics of Tourette’s Quieted by Cannabis
Studies show that cannabinoids act on the CB1 receptors in the basal ganglia, cerebellum, and hippocampus. This acting results in a dampening of motor and vocal tics.
The presence of multiple motor tics and at least one vocal tic characterizes Tourette’s syndrome. It is three to four times more prevalent in males than females and standard treatments are mostly ineffective, or associate with substantial side effects.
Some anecdotal reports point to the efficacy of nabiximols (Sativex®), consisting of THC and CBD in 1:1 ratio, as an alternative treatment strategy. Nabiximols comes in the form of a nasal spray, making administration easy and quick with accelerated onset of relief. While some initially thought THC alone might be an effective treatment strategy for patients with Tourette’s syndrome, later reports argued that THC in combination with CBD is superior.
Recently, a case report came out, describing a young Tourette’s syndrome patient treated with nabiximols. The initial dose was 2.7mg of THC and 2.5mg of CBD per day. Doctors slowly increased this to 24.3 mg THC and 22.5mg CBD. This treatment gave significant improvement in overall tic severity. A most importantly, also a 78% improvement in the quality of life.
No Side Effects
Additionally, the patient experienced no side effects and was able to tolerate the treatment well. Earlier case studies also saw reductions in tic manifestation by 70% with THC only (10mg/day). To date there are two clinical trials out, working with the same dose of THC; however both are double-blind, placebo controlled, and both report significant improvement in tic severity when using cannabinoids.
A significant body of evidence describes how endocannabinoids affect excitatory neurostransmitters in the brain, such as glutamate. These also look at inhibitory neurotransmitters, such as gamma amino butyric acid (GABA) and glycine, also dopamine, serotonin, noradrenaline and acetylcholine. The central CB1 receptor system likely regulates cannabinoids that reduce tics. In fact, the density of CB1 receptors is highest in the basal ganglia, cerebellum and hippocampus; areas of the brain that control the pathophysiology of Tourette’s syndrome.
Whether cannabinoids regulate the the number of CB1 receptors or the binding to CB1 receptors, or both, is still unclear. One study attempted to answer this question but due to the lack of control subjects, definitive conclusions could not be made. Nevertheless, they concluded that genetic variation in the gene encoding central CR1 is likely not the culprit for Tourette’s syndrome.
So far, the data has shown promising new avenues with cannabinoids in alleviation of tics in treatment-resistant Tourette’s syndrome. Large scale clinical trials are the next logical step in this realm of medical cannabis research. Indeed, the CANNA-TICS trial initiated in March 2017, in Hannover (Germany) represents an exciting new development in this field. The mission of the project is to design new therapeutic strategies. They aim to reduce side effects for patients with Tourette’s syndrome and adults with tic disorders.