In JAMA Network, researchers have published the first robust clinical study proving that medicinal cannabis effectively treats the debilitating effects of Tourette syndrome. Their findings show a statistically and clinically significant reduction in motor and vocal tics in as little as six weeks.
The researchers’ analysis found a significant association between levels of cannabis in the bloodstream and the response to active treatment.
THC (tetrahydrocannabinol) is the psychoactive compound in cannabis that produces a ‘high’ effect, while CBD (cannabidiol) is a non-psychoactive compound. Both are used medicinally in Australia.
Study co-author Professor Iain McGregor, the Academic Director of the Lambert Initiative, said: “We were delighted to be able to work with Professor Mosley and this team to deliver this important clinical trial showing the efficacy of oral THC and CBD in treating Tourette syndrome.
“This is such a difficult syndrome to treat. It severely impacts the quality of life of 1 in 100 young Australians. It is gratifying to know that our result provides strong evidence of an alternative treatment method for these patients in need.
“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.”
The study involved testing 22 adult patients with severe Tourette symptoms. In the double-blind study, participants received both medicinal cannabis oil and a placebo over two six-week blocks.
“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 clinical 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.
“In addition, we found that other symptoms associated with Tourette syndrome in our participants also reduced, particularly symptoms of obsessive compulsive disorder and anxiety.”
Tourette syndrome affects about 1% of the population and is four times more common in men than women. The neurological disorder often begins in childhood and is characterised by involuntary movements and vocalisations, or tics.
“Cannabis interacts with specific receptors on nerve cells in the brain that are part of the body’s own ‘endocannabinoid’ system,” Dr Mosley said.
“Effectively, stimulation of these receptors tightens a leaky filter that now stops the involuntary movements and vocalisations from getting out and being expressed by our participants.”
Source: University of Sydney
