If you’re a doctor and a younger patient uses a lot of cannabis, you’re likely going to worry about how that’s affecting their health.
That’s especially the case when, like Dr. Phil Tibbo, you’re treating a teenager or young adult for a significant psychiatric disorder like early phase psychosis.
Tibbo, who heads the Nova Scotia Early Psychosis Program at the Abbie J. Lane building in Halifax, figures about 80 per cent of his patients have some exposure to cannabis.
“Actually about 25 to 35 per cent would meet criteria for a cannabis use disorder,” said Tibbo, which can have “very significant negative outcomes” on their mental health.
Tibbo, who also teaches psychiatry at Dalhousie University, is exploring exactly how cannabis use is affecting his patients’ neurological activity, specifically in the white matter that acts as the brain’s communication system.
In a study that began last year, he and research collaborators at Western University in London, Ont., are doing MRI tests on the brains of patients who use cannabis regularly and others who have limited or no exposure to the drug.
They are also monitoring any behavioural or lifestyle changes through checkups at six-month intervals.
Early phase psychosis can manifest itself in obvious ways, such as auditory hallucinations and paranoid delusions, Tibbo said.
While those are the classical symptoms most people would be aware of, some forms of psychosis can be more subtle and not surprisingly the most difficult to diagnose.
“There’s also things we call thought disorders, not being able to think in the right way,” he said in a recent interview in his office. “There’s also what we call negative symptoms too (such as) lack of motivation or energy.”
A leading theory among neurological researchers like Tibbo is that psychosis is linked to disruptions in how connections are made among the different parts of the brain.
“So we’re trying to see if there is a link, and if we can show that link, between cannabis use in young adulthood, its effect on brain white matter, and subsequently its effect on psychosis development.”
The long-term benefits of the study, which is being funded by Research Nova Scotia and the Canadian Institutes for Health Research, could lead to a medication to treat the negative effects of cannabis on the brains of psychosis patients. Medications already exist that focus on abnormalities in white matter, outside of the cannabis effect.
“Say there’s an abnormality in the brain white matter, we see it. If we can show that specifically where and how that works and what that brain white matter abnormality is, then we may be able to look at bringing in some other medications that can actually help.”
Besides the psychosis patients, the study also involves participants from the public – young people who don’t experience psychosis. Like the patients, these participants have been broken into two groups of users and non- or limited users.
He’s also tracking the potency of the cannabis being used – the levels of THC – as well as whether participants are getting their stash legally at the Nova Scotia Liquor Corp. or in the black market.
Given that recreational cannabis use is now legal for adults in Canada, when it comes to its precise effects on the brain, particularly the developing brains of teenagers and young adults, the more we know the better, Tibbo said.
“The youth should be making their choices, but they should be making informed choices. … All the research, our research, really that’s what we’re trying to get. … To understand those interactions between cannabis and white matter, and long-term effects, but allow the knowledge to be translated to our youth so they can make the choice.”
Tibbo is still accepting participants for the study. Those interested can contact him through the psychiatry department at 902-473-1678.