Thank you for having me.
It's a pleasure to be able to speak in front of this committee on veterans.
I'm a professor of psychiatry at the University of Toronto, and an addiction psychiatrist. I think the previous speaker covered a little bit of what I wanted to say.
I have been doing research for many years now on cannabis and mental illness, in particular on the harms that come with that. I have studied people with psychotic disorders like schizophrenia, mood and anxiety disorders like depression and bipolar disorder, and even post-traumatic stress disorder—PTSD. I think that now with legalization here there are tremendous opportunities to understand the effects both on the general population and on people with specific mental health disorders.
The preponderance of the evidence—and I'm very delighted that licensed producers are actually doing this research—actually suggests a fair amount of potential harm in people with psychotic and mood disorders. Even in the PTSD literature, this is quite mixed right now. Again, I applaud the research being done in this area. Moreover, I think the reduction in the compensable grams per day of medicinal cannabis from 10 to three grams was a step in the right direction by Veterans Affairs Canada, just because of these harms.
We know that these harms in particular relate to two things. Number one is the content of THC in cannabis. That's tetrahydrocannabinol, which produces the “high” and many of the positive effects but is also related to harm. The other thing that counteracts that is this other cannabinoid, CBD or cannabidiol. Essentially, the ratio of those two dictates safety. The lower the ratio, or the more CBD that's in cannabis of any form, recreational or medicinal, the more it's going to potentially lower the harms.
The other thing I just want to state is that whether folks are getting medicinal cannabis—our veterans who are getting medicinal—or using recreational cannabis, there is going to be a subset of them, probably between 3% and 5%, who develop cannabis use disorder, as we call it in the medical field. The key thing I want to state about that is that it's a treatable disorder. There aren't any medications yet approved for that, but there is a lot of research in treating problematic cannabis use. There are lots of behavioural therapies and talk therapies that are not widely accessible. If our veterans are going to be at risk for developing these disorders, we want to do everything we can to put evidence-based treatments in place so that we can treat problematic cannabis use. It doesn't have to be a psychiatrist or a psychologist. Any willing provider can do that.
In summary—and again, I want to thank you for having me billed to come to speak to you—I think there's tremendous progress that has been made in understanding medicinal cannabis. Now with recreational cannabis, it's very likely that we could see increases in the rates of overall use in the population, including in our veterans. We want to do everything we can to control or limit the amounts of THC because we know that at a certain point it's going to do harm, particularly with developing brains and for people who are at risk or who have existing psychiatric disorders and mental health issues. We have treatments that can work.
Thank you for the time and for having me.