AN AUSTRALIAN-first study of medicinal cannabis as a treatment for the debilitating neurological condition Tourette syndrome is set to be launched in Brisbane.

Wesley Medical Research Institute neuropsychiatrist Philip Mosley will trial a medicinal cannabis product in 24 adults with severe Tourette syndrome – a disorder which begins in childhood and is characterised by involuntary movements and vocalisations.

Many people with the condition also experience anxiety, depression and obsessive compulsive disorder.

The condition is associated with bullying and poor academic performance in childhood and adolescence, and with unemployment and social isolation as an adult.

Existing treatments include antipsychotic medications, which suppress involuntary movements, but they are also associated with severe side-effects, including weight gain and high cholesterol.

Dr Mosley said deep brain stimulation was also effective in Tourette syndrome patients but it was costly and highly invasive, requiring surgery.

“The people with Tourette syndrome who’ve had deep brain stimulation are doing well, but not everyone wants to have brain surgery,” he said.

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Dr Mosley said he expected the medical cannabis trial to begin mid-year with a pharmaceutical product containing a mixture of cannabidiol (CBD) and tetrahydrocannabinol (THC) – two of the chemical compounds in cannabis.

“We think it’s a combination of the two that will hit the sweet spot,” he said.

Dr Mosley suspects THC alone may benefit Tourette syndrome patients. But because of concern about its psychoactive properties, which may increase anxiety and precipitate psychosis, he hoped that by adding CBD it would reduce the potential for harmful complications.

The treatment will be given as a tablet or in liquid form.

Dr Mosley said many doctors were unwilling to prescribe medicinal cannabis because “there’s very limited evidence for it for most conditions”.

“I think doctors are rightly cautious,” he said. “I’m hoping that this trial, if it’s beneficial for this condition, will enable doctors to prescribe with more confidence if they have a patient with Tourette syndrome.”

The trial has been made possible through a $100,000 grant from the Wesley Medical Research Institute.

For more information about the trial, email study co-ordinator Tracy Grierson at tgrierson@wesleyresearch.com.au