Results from a small but “robust” clinical study in Australia indicate medicinal cannabis can effectively treat the debilitating effects of Tourette syndrome.
Usually developing in childhood, Tourette syndrome is a condition with no known cure that is characterised by rapid, repetitive and involuntary muscle movements and/or vocalisations; also known as tics.
While earlier research has suggested successful treatment of Tourette syndrome with cannabinoids, a trial funded by the Wesley Medical Research Institute, Brisbane, and the Lambert Initiative for Cannabinoid Therapeutics at Sydney University has established this to be so.
The trial, originally announced back in 2018, commenced in 2019; but it’s only just now the results have been published.
The study was a double-blind, crossover trial involving participants with severe Tourette syndrome who were randomly assigned to a 6-week treatment period with increasing doses of an oil consumed orally containing 5 mg/ml of THC and 5 mg/ml of CBD. This was followed by a 6-week course of placebo, or vice versa, separated by a 4-week washout period.
“This is the first rigorous and methodical trial of medicinal cannabis to be undertaken in a sufficiently large group of people to make definitive conclusions about its effectiveness,” said neuropsychiatrist Dr Philip Mosley, who led the trial. “It shows that medicinal cannabis can reduce tics by a level that makes a life-changing difference for people with Tourette syndrome and their families.”
Dr. Mosley said other symptoms associated with Tourette syndrome were also reduced, particularly obsessive-compulsive disorder and anxiety symptoms.
One of the participants, Chris Wright, said the cannabis oil formulation reduced his tics by about 50 percent. But there is a trade-off – because the oil contains THC, patients are unable to drive a vehicle or operate heavy machinery. But this could be a comparatively small price to pay to experience symptom relief.
The most common adverse effects reported were cognitive difficulties – including slowed mentation (mental activity), memory lapses, and poor concentration. Cognitive issues were experienced by 8 participants.
“While there are well-known concerns about the side effects of THC on cognition and mental health, this trial demonstrates that careful dosing with THC in an oral formulation is very well tolerated in a relatively young patient group,” said study co-author Professor Iain McGregor.
Tourette syndrome affects around one in one hundred people, so to have a comparatively safe medication that is effective could make a huge difference to outcomes for these patients.
The study has been published in the New England Journal of Medicine: Evidence.
