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The Dose Transcript for February 15, 2024

Host: Brian Goldman

BRIAN GOLDMAN: Hi, I'm Dr. Brian Goldman. Welcome to The Dose. Cannabis has been around for a long time. Since legalization, stores have been selling products that contain higher amounts of the active ingredient tetrahydrocannabinol or THC. There's a lot. We're still learning about how those higher amounts of THC affect our bodies and our minds. On White Coat Black Art, we interviewed a young man who experienced intensely negative mental health effects from high-potency cannabis. You can find it at cbc.ca/whitecoat. So this week on The Dose, we're asking, what do I need to know about high-potency cannabis? Hi, Philip, welcome to The Dose.

PHILIP TIBBO: Hello there. Pleasure to be here.

BRIAN GOLDMAN: How often do you treat patients who use high-potency cannabis?

PHILIP TIBBO: I work primarily with youth and young adults in what we call early intervention services for psychosis. With that, we have about over, you know, 80% of our youth and young adults who have exposure to cannabis, about 30 to 40% who may have a cannabis use disorder. And the majority of those would have been using high-potency cannabis.

BRIAN GOLDMAN: Can you give us a hi, my name is? Tell us what you do and where you do it. Just adlib.

PHILIP TIBBO: Hi, my name is Dr. Phil Tibbo. I am professor and the Dr. Paul Janssen Chair on Psychotic Disorders at Dalhousie University in Halifax, Nova Scotia. I'm also the director of research for the department, and I also have a few other hats, including being president of our national organization on early intervention programs for psychosis in Canada.

BRIAN GOLDMAN: Let's begin by asking a straightforward question. What do we mean by high-potency THC?

PHILIP TIBBO: I think people get confused sometimes when we talk about potency. And as you mentioned, it is related to the active or the psychoactive ingredient in cannabis, the tetrahydrocannabinol, which we call THC. And so potency is really just the, you know, THC percentage by weight of the product. And so when we're talking about high-potency, that bar has been moving over the years. And today, we would say high-potency product is anywhere above 15% THC.

BRIAN GOLDMAN: And how does that compare to your parents’ or your grandparents’ cannabis?

PHILIP TIBBO: As you mentioned, we've seen the percentage of THC, the potency of product really increase over the last 40 to 50 years. I mean, the native cannabis plants, the, you know, more natural plant, there’s only about 1 to 2% THC. And we've seen that increase over the years. I mean, even within Canada, our data from Health Canada has shown that, you know, the average THC percent in the 1980s was around 3%. And around 2019, that was around 15%. And, you know, even since then, we've seen that increase significantly so that, you know, the market share of cannabis and the potency of products that's being sold is above 20%, 25% and higher. And, you know, and what we're seeing, you know, here in Canada is reflective in other areas of the world as well. We've seen that increase in potency of product in the reports of studies out of the U.S., out of Europe as well. So it is a global phenomena too.

BRIAN GOLDMAN: Is the greater potency always the result of cultivation, or are you seeing patients, clients who've consumed other synthetic products?

PHILIP TIBBO: It's a bit of both. Over the years, the potency of sort of the dried flower is more of a result from, you know, plant genetics and specific breeding within plant biology as well to produce a product that has higher potency THC. You can only go so far with that. And then some of the other products that we get on the market are derived in other ways as well. Then you may get into the products like shatters and waxes, which are about 80 to 90% THC. So that's fairly significant. And then as you mentioned, we also do have the synthetics. So that's not related to, you know, the parent plant at all. This is, you know, it's been derived in a lab. And that's very significant. It's a different product altogether but very, very high-potency for synthetics as well.

BRIAN GOLDMAN: So what are the usual psychoactive effects of high-potency THC?

PHILIP TIBBO: You know, people use cannabis because of the psychoactive THC. It gives you that euphoria. Basically, with a high-potency product, that is just all exaggerated, right? So it is a more exaggerated effect than what you would get with a lower potency product. So the same thing you would get with the low potency product, but it's just more of it and it could last longer as well.

BRIAN GOLDMAN: And what are the toxic effects of high-potency THC? I know you're not a toxicologist, and maybe you're just hearing this from your patients, or maybe, you know, if your patients end up in the emergency department.

PHILIP TIBBO: I guess it depends on how you want to define toxicity as well. We know that high-potency product can increase risk for some negative outcomes, and specifically with some negative outcomes around mental health and addictions as well. To me, that still falls within toxicology and toxic states as well. You know, a lot of research has shown that, you know, that increased potency actually increases your risk for development of a cannabis use disorder. For example, if somebody starts using cannabis with a high-potency product, they’re about even three times higher risk of developing a cannabis use disorder than somebody who starts with a lower potency product. And of course, the other concerning thing too is that there's a lot of significant research that has shown that association between high-potency product and the development of a psychotic disorder. So to me, this is still toxic effects of high-potency product.

BRIAN GOLDMAN: What about anxiety or agitation?

PHILIP TIBBO: That definitely can play a role as well. Now, interestingly, if you look at some recent systematic reviews on this whole topic, they've looked at all the studies that have looked at anxiety and depression with respect to potency and low potency product. The findings are still a little bit mixed, but that also indicates that there are still some people where high potency product can actually worsen anxiety and even worsen depression as well.

BRIAN GOLDMAN: And that's interesting because of course, one of the reasons why people consume cannabis products is to not just get a bit of a buzz, but to get relaxed. And when I think relaxed, I think reduction in their anxiety.

PHILIP TIBBO: No, that's very true. And you get into some good discussions with people, with patients about that very same cycle is that that's initially why they started. But then what they're finding that over time, actually, their anxiety is worsening. And oftentimes, it is related to, you know, being sold and maybe not having the right knowledge about the product that they're purchasing and realizing afterwards that, hey, this is really high potent product. Maybe that's why my anxiety is actually getting worse.

BRIAN GOLDMAN: As you've mentioned, high-potency products are generally recognized as being over 15% THC, containing over 15% THC. But from what I've seen, there is no recognized definition of high-potency.

PHILIP TIBBO: Very true. And this is actually even a bit of an issue with respect to some of the research as well. You know, how do we define high-potency products? Back in the 80s, when generally it was around 3% THC, we would have called high-potency product anything around 10%. And some of the studies out of Europe have called high-potency product anything above 10% as well. I just see that bar moving. And now, with market shares being 20 to 25% THC, we continue to go and change that bar as to what THC high-potency product will be. And that is one area that we need to work on, is really defining what we call high-potency. Generally, in the research and clinical literature as well, there's a general understanding about 15% being that line.

BRIAN GOLDMAN: As an emergency physician, I see patients who've taken much higher potency THC. And it's in that environment, the emergency department, that we see patients who have more of the physical effects of consuming high-potency THC. So we see a lot of patients who have nausea and vomiting. And then there's this thing called the cannabis hyperemesis syndrome, people who are vomiting and, you know, it's hard to relieve. And we're scratching our heads because we're looking for things like appendicitis, gastroenteritis, a bowel obstruction. Have they had prior surgery? And none of that is true. And then you go back and then the penny drops and you ask them, have you been consuming marijuana? And the answer is yes, I have. And have they increased their consumption?

PHILIP TIBBO: No, great point. And actually, my research group here, one thing we're doing is actually a large study looking at all-cause cannabis related presentations to the emergency department, and that hyperemesis syndrome is definitely one thing that brings people too. And interestingly, we're not quite clear yet on what are some of those risk factors for developing it. It's not necessarily new. And in some people, it's more chronic, but it can be severe enough to bring people to the emergency department. The one thing I think, and you brought up a point there, is that, you know, it was after the fact, you know, the emergency room doctors maybe have gone back to ask about cannabis use for any presentations. And I think, you know, with legalization within the Canadian setting, within the emergency departments, we're kind of now just getting there where we're asking those questions in the emergency department and being able to see, you know, what effects, you know, this cannabis use can be on their presentations for all-causes, both physical and mental health.

BRIAN GOLDMAN: Another thing that we see in the emergency department are patients who push their use of cannabis to what I would call extremes, and some of them will have high blood pressure, delirium, and in a small minority of cases, seizures. I haven't seen a patient who's had cannabis induced seizures, but my reading of the literature suggests that that's possible.

PHILIP TIBBO: It's definitely possible. I will say it's somewhat rare. And oftentimes, we will see that more with synthetics, because again, the synthetic cannabis is a different kind of product altogether. And we will see there's incidents of seizures but also of stroke and actually even death with the synthetics as well.

BRIAN GOLDMAN: We're coming to a point. From the standpoint of toxicity, how much THC is too much?

PHILIP TIBBO: So many variables are at play there too, because you also have to consider its high-potency product. Is it just on one occasion or is it regular use of high-potency THC? Is it the 20%? Is it the shatters and waxes that are 80 to 90% THC? And that is also the individual's response to cannabis as well, because as you know, people respond differently to cannabis. Really, the education that we need to get out there is that the whole idea on taking cannabis is that it's supposed to be a pleasurable experience. If it's not, well, then you're probably at risk for some significant negative outcomes.

BRIAN GOLDMAN: Certainly, when I've done columns on the adverse effects of cannabis, I get significant pushback from people who say that cannabis is safe because it's been around for centuries. I'm sure you've heard that before.

PHILIP TIBBO: Yes. And generally, cannabis can be safe as well. Now, keeping in mind there's a few things there too is that it's been around for centuries. True enough. But the product that we're using today, that's available to our youth and young adults and to the population today is completely different than even what it was 10, 15 years ago. It's a bit of a leap to make that assumption that it's the same for centuries because no, it is a different product with respect to potency that exists and is around today as well.

BRIAN GOLDMAN: In addition to there being different products, there are many ways these days to consume cannabis, not just smoking as it used to be, or primarily, you have edibles, you have vaping. To what extent does the method of consumption bear on adverse effects?

PHILIP TIBBO: You're right. Mostly, and still the majority of the way people use cannabis, if you look at our Canadian cannabis surveys that the federal government does per year, still, the most common use is smoking. Like smoking dry flower product. But the rates of vaping are increasing, plus as well, the rate of edible use too. And each one of those have some things to consider. For example, edibles, you know, it just takes longer to get the effect. So some people who are not used to using edibles may feel that they're not getting the effect that they want and take more and continue to take more, and eventually they get into that toxic state because they've just taken way too much. For vaping, unfortunately, most of the product that you get within the vaping constituents are high-potency product. So that's where you get 80 to 90% THC in the vaping cartridges. So that is that increased risk as well. And one thing we haven’t mentioned, of course, is just with lung health as well, right, with any kind of inhaling.

BRIAN GOLDMAN: Is it fair to say right now, Philip, that we don't have a lot of data on the impact of vaping THC, for example, and maybe there's a lot of variation in the quantities of THC that will be consumed through vaping?

PHILIP TIBBO: I definitely agree with that. There has been some good research going on, but we definitely need much more. We need the funding for this research to occur. And I think we've seen that evolution within the research into this as well is that, you know, we've moved on from just using cannabis or not using cannabis. Now we need to include in all those studies how much cannabis you're using, potency of product and being able to really, for us to fine tune our understanding of the effects of cannabis use.

BRIAN GOLDMAN: How does the impact of high-potency THC affect young people in a way that's, you know, say under the age of 25, that may be different to people who are over the age of 25?

PHILIP TIBBO: Interesting. We always come up with that 25 year number as well. Really, what we're talking about is the effect of cannabis on that still developing brain, because neurodevelopmentally, our brain isn't really done with its development until we hit that mid-twenties cut off mark. All the myelination, all the kind of connections that are happening with all the different parts of the brain all occurs during that time period. And adolescence is a huge part of brain development to that kind of final match race style processes. So this is why there's been a lot of attention on the effects of cannabis within that youth and young adult population. And sure enough, what we see is that, again, high-potency product does affect that risk of developing a cannabis use disorder. And actually, even the severity of the cannabis dependence is related to what potency of product that you start with and are using during adolescent young adults. And with respect to mental health, we've seen that use within youth and young adults being quite related to the development of psychosis and psychotic disorders as well.

BRIAN GOLDMAN: It's interesting what you were saying about age 25. Obviously, that's an arbitrary figure. You know, my reading of the studies that have been done that have looked at the impact of THC on the developing brain compared to the fully developed brain is that by choosing age 25, the researchers have chosen a conservative figure. By the age of 25, the vast majority of people have had full brain development.

PHILIP TIBBO: That's true. Yes.

BRIAN GOLDMAN: We're coming to some practical questions right now and to some bottom line. So when it comes to high-potency THC, what would you say are safe consumption guidelines?

PHILIP TIBBO: Yes. So I think when it comes to the high-potency product, what we always tell, I think there's two ways of doing it. And it's both informing our public health guidelines, but as well even any policies on cannabis sales as well. And this comes in to both of these as well. The lower the potency, the better it is with respect to negative outcomes, right? So if you can use a product that first is below 20%, but even if you can get it lower, a bit lower, you know, 15 and 10%, what you're doing is you're reducing your risk of potentially negative outcomes. So we're not necessarily telling people to not use. We want people to be able to use in a responsible way and to have the knowledge to ensure that they don't have any of these particular negative outcomes. So potency of product. We always say, you know, just be able to know, to be able to ask, where you buy and what you buy, and knowing what your THC potency is of the product that you're buying, and just the lower the better.

BRIAN GOLDMAN: And what about people whose brains are developing? I'm referring to younger people, of course.

PHILIP TIBBO: There are a few sort of low risk guidelines that exist. And usually for younger people, we say, you know, if you cannot use, first of all, that's probably better for you. But as well, if you're in that youth and young adult population and you're using, stick to the low THC potency product. And in addition to that, be careful of how much you use as well. Canada still has a high rate of daily or almost daily use within a young adult population, and we have to think and educate and move away from that as well.

BRIAN GOLDMAN: In your practice, do you find yourself diagnosing substance use disorder with respect to THC, so that you actually diagnose THC use disorder in some of your patients?

PHILIP TIBBO: Oh, definitely. Yeah. So when we say cannabis use disorder, it's not uncommon within our particular population.

BRIAN GOLDMAN: And how do you define that?

PHILIP TIBBO: There is specific sort of criteria to be met to get a diagnosis of cannabis use disorder. Those criteria, basically, it's a little bit of a laundry list as well, but generally, it's any kind of problematic pattern of cannabis use that can lead to some significant impairments in various areas.

BRIAN GOLDMAN: Such as?

PHILIP TIBBO: Well, such as psychosocial functioning, how you're doing at school, how you're doing at work, but as well as having that craving or strong desire, continued use despite negative outcomes, but as well as things like tolerance and withdrawal symptoms as well.

BRIAN GOLDMAN: How do you encourage people at risk to cut down on THC potency and more frequent use? I guess we could divide that into those who have a defined cannabis use disorder and those who don't.

PHILIP TIBBO: True. I mean, that's the first thing. So if somebody comes with a cannabis use disorder, obviously, there's some severity there with respect to functioning, and we have to try and get that individual out of that cannabis use disorder. And then we talk about harm reduction techniques, right, and how you can approach that. And sometimes, the very first harm reduction technique that we use, which is just trying to get some people to buy from licensed sellers because we know then there's better control and knowledge about actually what the THC percentage is of the product that they're buying. Sometimes, that's just the first step. And once we know that, then we can start looking up other products and being able to say, okay, let's just look at what's available at a lower THC potency range, and we'll sort of address it in that way. And keeping in mind there's always the potency end of things, but there's also around that daily or almost daily use that we have to try and address as well.

BRIAN GOLDMAN: Do you have any tips for parents of young people who may be consuming greater and greater amounts of cannabis, on ways to get them to cut back?

PHILIP TIBBO: There's actually some really good literature there within our Canadian system as well for parents on how to talk to your kids about cannabis use. That exists to really allow parents to kind of develop a language, know what questions to ask. Although difficult for parents sometimes to be able to know how to ask those questions in kind of a non-judgmental way, in a way that will allow you to have a conversation with your child versus that child, you know, kind of putting up the wall and not having that conversation as well. Part of this too is just having that conversation around the dinner table. I mean, being upfront and asking about cannabis use. Hey, what do you use? What kind of product? Where are you buying? Where are you getting it from? Then having that knowledge to say, hey, you know what? Be careful of how much you're using, the frequency, but as well as that potency of product. And also, if the parents know what resources may exist in their community, that may help further that education as well for their youth and young adult.

BRIAN GOLDMAN: We've been talking about high-potency THC most of the time here. But when it comes to lower potency THC, there are precautions that people should take.

PHILIP TIBBO: If we look at the things, or the variable is what we say, that lead to some negative outcomes, one that is there is again that amount of use, right? So even at low potency cannabis, still daily or almost daily use will lead to, potentially lead to more negative outcomes. So that is still something to consider as well.

BRIAN GOLDMAN: And of course, you know, one precaution is not to use and drive immediately afterwards.

PHILIP TIBBO: Of course. Yeah. Not only just driving, but sort of workplace as well, if somebody is within a particular job or situations where cannabis use is going to affect not only their focus and attention, but even sort of manual hand dexterity skills as well.

BRIAN GOLDMAN: Well, Dr. Philip Tibbo, thank you so much for sharing your knowledge on cannabis and cannabis use disorder with us on The Dose.

PHILIP TIBBO: My pleasure.

BRIAN GOLDMAN: Dr. Philip Tibbo is a professor in and the director of the Department of Psychiatry at Dalhousie University. Here's your dose of smart advice. One of the key active ingredients in cannabis is tetrahydrocannabinol or THC. The potency of cannabis is generally expressed as the percentage of THC contained in the product. Naturally occurring cannabis plants contain 1 to 2% THC, and genetically modified plants are cultivated to boost the percentage. The cannabis that was around from the 60s to the 80s generally contained 1 to 5% THC. Today's versions are often much more potent. There is no universally accepted definition of high-potency THC. In general, anything above 15% is considered highly potent, and today, there are a lot of commercially available products that contain THC greater than 20%. High potency can cause adverse effects. These include nausea and vomiting, abdominal pain, high blood pressure, anxiety, agitation, delirium and seizures. Another serious adverse effect is called cannabis induced psychosis, whose symptoms include hearing voices or auditory hallucinations, feelings of being persecuted, grandiosity and depersonalization, which is the feeling of being detached from one's body or mental processes. Young men, and especially those with a family history of psychosis or schizophrenia, are more likely to experience cannabis induced psychosis from consuming high-potency THC products. Another important variable is the method of consuming cannabis. We know less about the toxic effects of consuming high-potency edibles and vape. But for instance, some studies suggest that vaping high-potency THC products may produce more adverse effects than smoking the same dose. Several variables may determine whether you have adverse effects, so it's difficult to figure out a dosage or THC potency that's universally safe. Adverse effects do not happen to everybody who uses high-potency THC products. In general, use products that contain the lowest possible potency of THC. Because THC has a greater effect on the developing brain, young people should postpone their use of THC products until they reach the age of 25. Because of the risk of cannabis induced psychosis, young men under the age of 25 with a personal history or a family history of psychosis or schizophrenia should avoid high-potency THC altogether. Finally, depending on frequency of use, most forms of THC can cause drowsiness and impairment behind the wheel. When consuming cannabis, wait at least six hours before driving a car or operating dangerous machinery. If you have topics you'd like discussed or questions answered, our email address is thedose@cbc.ca. If you liked this episode, please give us a rating and review wherever you listen. This edition of The Dose was produced by Sameer Chhabra. Our senior producer is Colleen Ross. The Dose wants you to be better informed about your health. If you're looking for medical advice, see your health care provider. I'm Dr. Brian Goldman. Until your next dose.

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What do I need to know about high-potency cannabis? - Transcript

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