Health Committee on May 27th, 2014

[Mark Asbridge]

I just want to touch on one of the other areas in which we've done some work, and that is how we define harmful or problematic cannabis use. A national and international group I work with has looked at how we define this issue. I know it's an issue of concern for the committee.

Simply put, there are various tools that are used by clinicians to assess or screen for problematic use. These tools include the WHO's ASSIST, for instance, and others, such as the CUDIT, the cannabis use disorders identification test. These tools are used to identify people at potential risk for cannabis misuse and problems.

When we look at this issue, we find that these items typically set the threshold or the bar too low. These items typically identify any use as being problematic use, so we see them as not very useful tools. What often gets looked at is simply whether somebody uses and the frequency of use.

For instance, with the ASSIST tool, you could use cannabis once a month and be identified as being a problematic or harmful user, and that would over-screen people from a health care perspective. That would be a terrible tool to identify problematic use. What gets excluded are true problems related to use that might be experienced by the individual. I think we have to be careful when we use these kinds of tools to identify problematic use, and we must consider broader issues around real harms that might be affecting the individual.

One of the things we looked at is that it's maybe more important to measure the quantity of consumption, as we do with alcohol. We can draw on the alcohol literature here. Quantity is more important than frequency. Bingeing is more important than regular use of one joint a day. It would be more important to look at somebody who smokes in excess of three or four joints in a single sitting at more irregular intervals or at somebody who uses multiple joints in a particular day. Drawing on the alcohol literature, I think quantity is something that's not considered strongly enough when we're looking for problematic and harmful use.

I have a lot more to say, but I'll leave my points right here and answer questions.

[The Chair, Conservative, Ben Lobb]

Thanks very much, Mr. Asbridge.

Next up is Mr. Wood.

Welcome. Thank you. We know it is early out your way, but thank you again.

You have 10 minutes to present.

[Dr. Evan Wood, Director, BC Centre for Excellence in HIV/AIDS, Urban Health Research Initiative, As an Individual]

Good morning. Thank you so much for giving me the opportunity to speak. I have some brief prepared remarks and then I'd be happy to take any questions.

By way of introduction, I'm a professor of medicine at the University of British Columbia. I hold a Canada research chair in inner city medicine. I am the medical director for addiction services at Vancouver Coastal Health and I'm an American Board of Addiction Medicine accredited addiction medicine physician.

Today I will summarize some of the health harms of cannabis at the individual and public health levels and hopefully offer some insight into how these harms can be mitigated.

In recent years research has concluded that cannabis can contribute to some health harms, although I think in many instances these have been overstated, and I'd be happy to talk about in which instances I think they have been. As previous presenters have noted, while these health harms are a matter for concern, especially among vulnerable populations, relatively speaking, the health harms of cannabis in terms of individual health are believed in the scientific literature and in the medical community to be less serious than those of tobacco and alcohol.

Most importantly, I should note that cannabis is one of the most commonly used, certainly the most commonly used illegal drug. Most users use it infrequently and with no obvious harms to themselves.

I really come to this issue from a conservative perspective with respect to government accountability and the need for impact assessment of taxpayer-funded interventions. As you are likely aware, despite more than an estimated $1 trillion spent in the last 40 years trying to suppress the drug market in general, cannabis remains freely available to young people in our society. In many respects it is more accessible to young people than alcohol and tobacco. There are statistics from various U.S. government-funded sources, including the Monitoring the Future study, that show that about 80% of young people find cannabis easy to obtain.

In recent decades, rates of cannabis use have climbed; cannabis potency has increased, and the price of cannabis has decreased. Despite our best efforts in public education and law enforcement, it's clear we've not been able to effectively curb cannabis supply and demand, and importantly, a violent unregulated market has filled the void to supply cannabis to consumers.

The Fraser Institute, an economic and public policy think tank, has estimated that the market for illegal cannabis in British Columbia may be as large as $7 billion per year. This is more than double the total revenue from the province's agricultural, forestry, and fishing sectors combined. The well-intentioned efforts to reduce the availability and use of cannabis by making it illegal, like alcohol prohibition before it, has had a range of unintended consequences in terms of its contribution to organized crime. It's important not to separate the cannabis market from other illegal industries. For instance, the RCMP has done a very nice job describing how the export market for cannabis to the United States contributes in a substantial way to the importation of cocaine and guns into Canada.

Economists considering this issue have helped me understand that this is just simply the laws of supply and demand; that is, any consequential intervention into the cannabis market that in any way reduces supply will have the perverse effect of driving up the price of cannabis and incentivizing new individuals to get into the marketplace. In light of the harms of cannabis use and the social harms of cannabis prohibition the question is: what should be done next?

It's commonly argued that rates of cannabis use would be higher if law enforcement measures such as these were not in place, which raises the question: should anti-cannabis provisions be strengthened? Importantly, the scientific evidence does not supply this approach. A survey of UN member states that looked at how aggressively anti-drug laws, including anti-cannabis laws, were enforced demonstrated that there's no association in per capita rates of use in relation to how aggressively anti-cannabis prohibition are enforced.

Quite the contrary, settings with softer laws with respect to cannabis, such as the Netherlands, where cannabis has been de facto legalized, are lower than in settings where anti-cannabis prohibitions are aggressively enforced, at least traditionally, such as the United States.

While you've already heard from other speakers that the cannabis available on our streets is more potent than ever before, it's important to note that this has happened despite escalating expenditures aimed at reducing the cannabis supply. Our best efforts to limit supply and demand have not been successful. As a result, cannabis is freely available throughout the country in an unregulated way and to the benefit of organized crime.

As a physician and researcher, I stand with leading public health bodies, including the Health Officers Council of British Columbia and the Canadian Public Health Association, which have argued that we should be looking at the taxation and strict regulation of adult cannabis use as the best way to wage economic war on organized crime, and certainly to have the potential to better protect young people from the free and easy availability of cannabis that exists under prohibition.

I'll stop there. I'm happy to answer any questions that members of the committee may have.

[The Chair, Conservative, Ben Lobb]

Thank you, Dr. Wood.

Next up we have Mr. Jutras-Aswad. Sir, you have 10 minutes.

[Dr. Didier Jutras-Aswad, Assistant Clinical Professor, Psychiatric Department, Université de Montréal, As an Individual]

I want to thank the committee for inviting me to talk about what, in my opinion, is probably one of the most controversial but also very scientifically challenging topics in mental health. Talking about mental health and addiction, psychiatrists leading the addiction psychiatry unit at the Centre hospitalier de l'Université de Montréal, also leading a laboratory focusing on the endocannabinoid system and the neurobiology of addiction....

I have the chance to follow, I think, an amazing group of highly skilled very renowned researchers that probably talked about a lot of different aspects of the risks related to cannabis. Therefore, I'll be able to focus on a very specific aspect of cannabis and risk that's related to that substance. That is basically the content of cannabis, which in my opinion is one of the very important factors to take into consideration when trying to understand the risks that can be related to cannabis.

As a general introduction, one thing that is very interesting at this point in science related to cannabis is actually the growing understanding we have of the neuroscience of addiction, and more specifically the understanding of the endocannabinoid system, which is what we now understand to be main compounds that are found in cannabis, namely THC. I think that understanding really allowed us to get a better sense of what the short-term and long-terms effects of exposure to cannabis are. Also, the emerging knowledge that we have now, that we'll talk about very soon, is about the content of cannabis, which is a very complex substance.

As you probably have heard, there are different outcomes that have been assessed in relation to cannabis exposure. Obviously, there are some very specific outcomes related to mental health that have been very well studied, including: the relationship between cannabis exposure and psychosis; between cannabis exposure and the risk of developing addiction to that substance but also other substances; the relationship between cannabis exposure and the risk of developing anxiety and depressive disorders, as well as developing learning and cognitive problems.

In the last five to ten years, probably more the last five years, in the neuroscience world and also the clinical and the addiction psychiatry world, the growing knowledge that really highlighted and put a new light on the association between cannabis exposure and various outcomes is the fact that clearly all are not equal in front of cannabis exposure. By that I mean, very clearly, when you look at the general population who are not vulnerable from a mental health or even a genetic perspective, the exposure to cannabis is quite rarely related to very severe long-term negative effects, including mental health.

What is clear now is also the fact that there are some factors that can really increase the risk of developing very significant negative effects when someone is exposed to cannabis. Among these factors, one is definitely genetics. When you look at all the data on the relationship between cannabis exposure and psychosis, certainly there are genetic factors that will definitely modulate the risk of developing psychosis when you're exposed to cannabis. Among other factors, obviously, is age. Probably other researchers have talked about the fact that age will definitely modulate the risk of developing, for example, cognitive problems when you're exposed to cannabis. The younger you are when exposed, the longer will be the term you'll probably have cognitive problems.

One of the factors, which is why I'm here and what I want to talk about today, that will clearly modulate the risk associated with cannabis exposure and other cannabinoids is actually what is found in cannabis. For a long time the main focus has been on THC, which in laboratory settings has been associated with a lot of the outcomes that I talked about—cognitive problems, psychosis, anxiety, for example—but now we have a really good understanding, actually a better understanding, of other cannabinoids that are found in cannabis. Clearly, there is not only THC. For example, there's cannabinol and also there's cannabidiol.

Why I talk about this is that all of these other cannabinoids that we find in cannabis are very different from THC. I'll give you an example. Clearly, when someone comes into a laboratory...and groups around the world have shown that when someone comes into a controlled setting and are administered THC in sufficient dosage, you'll see cognitive problems. You'll see psychotic symptoms. You will see anxiety symptoms very easily. On the other hand, when someone in a controlled setting is administered another cannabinoid, for example CBD, cannabidiol, you see very different effects. I'll give an example.

In the lab, when you administer THC to someone at a significant dosage, you will induce symptoms very similar to schizophrenia. If you pre-treat these people, these subjects, with cannabidiol, you can decrease the symptoms of psychosis. That's just to give you an example of how this drug is very complex, but different compounds will have a different effect.

That has very important implications in terms of how we understand the risks associated with cannabis, but also what kind of data we need to really be able to get a better sense of what the risk is associated with cannabis and also how to deal with changes in the laws and how we'll deal with, for example, therapeutic cannabis, if we were to go that way in society.

I think the implications are very important. First, I think the assessment of clinical effects and the risks associated with cannabis can only be made accurately if THC and CBD contents are taken into account, because depending on the ratio of CBD and THC, the effect of that substance can vary widely and very importantly.

The therapeutic use of cannabis is not a topic I talk about, but there is clearly some therapeutic potential for that substance as a whole, and it can only be made in a scientific evidence-based manner with rigorous control of the THC and CBD content. We know that each substance has a very specific effect, and if we want to use them in a therapeutic manner, we have to be able to control that, just as we do with all other medications.

In terms of research, I also think that significant research effort should be devoted to examining and discriminating the specific effect, but also the risk associated with THC and CBD. Studies looking at cannabis risk and therapeutic properties should consider THC and CBD content when looking at that association.

In terms of recommendations, if I can make some, as a general statement I think it's crucial to underline that much remains to be understood in regard to the deleterious effect of cannabis. The risk can only be truly understood by taking into account all the factors that can modulate that risk. Again, all are not equal in front of cannabis exposure. One of the major issues that needs to be solved is the understanding of the specific effects of the various cannabinoids that can be found in that substance, mainly THC and CBD.

In terms of regulation, I think that definitely the content ratio of CBD and THC should be taken into account as part of any regulation regarding cannabis, both for recreational purposes and for medical therapeutic use.

I also think that compound simple with high CBD and low CBD should be considered for now as potentially safer in the absence of more definitive data, based on what we have available in terms of scientific data on the effect of both compounds.

I definitely think that research related to other cannabinoids, including cannabidiol, but also cannabinol and other cannabinoids—there are dozens in cannabis—should be facilitated, including by alleviating some of the burdens that are related to the study of that substance. It's pretty amazing at this time that for a researcher, it's much more difficult to study specific compounds, specific cannabinoids, in an evidence-based, very strong scientific manner than it is to study a substance such as cannabis that will have a very different content. It is really difficult to study it as a medical compound for medical use.

I also think that regulations that pertain to other cannabinoids, including CBD, should be revisited. Actually, cannabidiol, which is anti-addictive, does not induce psychotic effects, is not abused on the street, is considered as dangerous and as addictive in terms of scheduling in terms of regulation as substances like THC that can be addictive, or other substances such as cocaine or heroin.

I'll be happy to take questions.

[The Chair, Conservative, Ben Lobb]

Thank you very much.

We're going to go into our first round. Ms. Davies, go ahead, please.

[Libby Davies, NDP, Vancouver East, BC]

I'd like to direct my questions to Dr. Wood.

First of all, thank you so much for getting up so early. I think there are at least three of us on the committee who have an appreciation of how early you had to get up to present to us today from Vancouver.

I know you've done a lot of research and you also have a lot of on-the-ground experience in Vancouver. This study that we're doing is quite restrictive in that it's only looking at the harms and the risks of marijuana use.

I have three questions that I want to ask you, and I hope you can answer each of them.

Relative to a whole number of substances, whether it's alcohol, tobacco, prescription drugs, or other drugs that are illegal, would you consider marijuana to be a lethal drug?

[Dr. Evan Wood]

Do you want me to take them one at a time?

[Libby Davies, NDP, Vancouver East, BC]

Yes, one at a time. I have two more questions after this one. We have seven minutes for back and forth, so we'll just keep our eyes on the time, too.

[Dr. Evan Wood]

Very quickly, a great deal of study has gone into looking at the relative harms of different psychoactive substances and pharmaceutical drugs. As I made clear during my remarks, there is broad scientific consensus, and I think people would be way outside that consensus if they were to place cannabis as being more harmful than alcohol and tobacco. Certainly, alcohol and tobacco are much more addictive and toxic.

In terms of cannabis, you're asking if it could be lethal. In terms of the physiologic properties of cannabis and the prevalence of use, those types of reports are almost non-existent in the literature. With confounding factors of poly-substance use and other things, cannabis itself is relatively safe. I agree with the former presenter and have personally seen individuals who have become psychotic from using high-dose cannabis, but that's a transient effect of cannabis intoxication. I've never seen anyone with persistent effects of that. I think it's important to note that alcohol, during intoxication and withdrawal, could make people psychotic.

So relatively, certainly it's much safer.

[Libby Davies, NDP, Vancouver East, BC]

Thank you, Dr. Wood.

I'll go to my second question.

I don't know if you are familiar with Kevin Sabet, from Florida. He presented as a witness at the committee. In fact, he has been widely quoted. He has an emphasis on a project called SAM, smart approaches to marijuana. I've been reading some material that disputes his credibility in terms of scientific evidence and whether or not he has peer-reviewed material.

I wonder if you are familiar with his work, and whether or not you have an opinion as to the credibility of the conclusions he presents.

[Dr. Evan Wood]

Yes, I know Kevin's work. Kevin tends not to conduct original research and is not part of the scientific community that's actively working in this area. He is known to work with policy groups favouring a shift from outright prohibition to a sort of prohibition light. I wouldn't place Kevin in the group of highly credible scientists who are working in this area who are taking a bit more of a nuanced approach.

[Libby Davies, NDP, Vancouver East, BC]

Does he have peer-reviewed papers that you're aware of?

[Dr. Evan Wood]

I haven't seen original scientific work from Kevin. I believe he has published commentaries and articles of that nature, but not work such as that presented today funded by the Canadian Institutes of Health Research, or my own work, funded by the U.S. National Institutes of Health.

[Libby Davies, NDP, Vancouver East, BC]

So he would be more of a commentator than someone who's actually done scientific research.

I have a third question, and you did partly address this in your comments. We're talking about substances that to varying degrees all provide harm. Probably the thing that we do every day in our lives that is one of the greatest risks is driving a car, right? We use seat belts. We try to mitigate the risks and promote a safe environment.

In your opinion, what provides better control and safety when it comes to marijuana? Is it prohibition, or is it regulation?

[Dr. Evan Wood]

That's a really good question. I think it's important for people to understand that there is a middle ground between prohibition and legalization. I alluded to the Health Officers Council of British Columbia, and the Canadian Public Health Association, which believes that the strict taxation and strict regulation of adult cannabis use would wage economic war on all the organized crime groups that control this market and better protect young people from the free and easy availability of cannabis. That's certainly my opinion as well.

[Libby Davies, NDP, Vancouver East, BC]

To follow up on that, one of the issues that Mr. Sabet puts forward as the reason we need to continue with a prohibition model is the higher potency of THC content over the years. It just strikes me that if we did have regulation just as we do for smoking or alcohol, that's something we could actually regulate. It would then produce a less harmful health risk. We could regulate in terms of adult use, as opposed to youth using.

In terms of regulation, I know the medical officers did a lot of work on this, but how do you actually see a regulatory regime in terms of managing the risks and harms?

[Dr. Evan Wood]

This has been a huge area of scientific inquiry with respect to looking at other substances, particularly tobacco and alcohol. How they're regulated, how they're supplied, in what potency, the outlet density you allow, and prohibitions on advertisement and promotion all can have a huge impact upon rates of use and related harms. That science could be lent to a regulated market for the taxation and regulation of the adult use of cannabis.

Certainly, things like potency or, as a prior speaker described, the relative potency in terms of cannabinol and THC are all things that can be controlled. The increasing potency of cannabis, we have to recognize, has emerged under prohibition, and there's the increased sophistication of the market in that context. We've totally handed over regulation to illegal bodies, and many of us strongly believe that if we take control of this market, we can regulate this type of thing.

[Libby Davies, NDP, Vancouver East, BC]

Thank you very much.

[The Chair, Conservative, Ben Lobb]

Thank you, Dr. Wood.

Next up for seven minutes is Ms. Adams.

[Eve Adams, Conservative, Mississauga—Brampton South, ON]

Dr. Jutras-Aswad, in very plain language, can you explain to me what a psychotic episode looks like and what a schizophrenic episode looks like?

[Dr. Didier Jutras-Aswad]

Actually, they're different things. You can have psychotic symptoms that include hallucinations, obviously, and delusions and ideas outside of the reality. That can actually occur in a lot of different kinds of circumstances, such as when you're severely depressed or when you have schizophrenia or a very severe psychotic disorder that is a more long-term disorder, but also when you're exposed to certain substances that can induce psychotic symptoms, such as, actually, cannabis, or cocaine, or a lot of other different drugs.

[Eve Adams, Conservative, Mississauga—Brampton South, ON]

Thank you.

I'm not sure if you're aware of a study from 2011 conducted by the Canadian alcohol and drug use monitoring group. It's a survey they ran, and it showed that in the last year.... They measured how many folks actually used marijuana. In 2004, 14% of the general population—they're extrapolating—had used marijuana at some point in the previous year, but by 2011 it was down to 9.1%. That's a statistically significant decrease. It's also a very sizable decrease. It seems as though it was much more popular in 2004 but was very much diminishing in popularity by 2011.

I guess we're somewhat concerned that all of a sudden this has become a political football, and people are trying to throw this out on the front pages and so on, when in fact there isn't this big clamouring for legalization or the ability to sell marijuana at every corner store. I'm particularly concerned about what the impact would be on the developing mind, about what those health consequences are.

This is actually our last day of testimony for this study. What we're struggling to find is independent scientific evidence that really speaks to the effects and the impact on individuals' health of using recreational marijuana, especially on developing minds. That study said that the overall population is really not using marijuana quite so much, but it did find, however, that youth really are using marijuana, and some of the numbers are really, really high. In the past year, cannabis use by youth was 21.6%, or three times higher than that of adults.

I guess the concern is that if you were to make marijuana readily available at variety stores and simply say that you needed to be a certain age in order to purchase it, similar to cigarettes.... I think we could all say realistically that we've seen teenagers smoking cigarettes, so somehow they have them in their possession. Have you undertaken any research on young participants, 13-, 14-, or 15-year-olds, to see what the health consequences are of recreational marijuana usage, or are you aware of any studies or science on this issue?

[Dr. Didier Jutras-Aswad]

I'm not sure if I understand the question. Is it about the availability of the drug, or whether the change in the law would make it more available for youth? Or is it about what the long-term effects would be?

[Eve Adams, Conservative, Mississauga—Brampton South, ON]

With regard to health, it's about whether you're aware of any science that has actually looked at the impact on the developing brain of using recreational marijuana. I assume that in the studies you were referencing they were of consenting adults over 18 or 19 years of age, but is there any science out there about what the impacts would be on the brain of a 12-year-old or a 13-year-old?