Health Committee on May 13th, 2014

[The Vice-Chair, NDP, Libby Davies]

We're ready to start the meeting. Our chair, Ben Lobb, is away today, so as vice-chair I agreed that I would chair the meeting.

Welcome, everybody, and to our witnesses.

We're continuing our study on marijuana's health risks and harms. Today we have two witnesses, Dr. Walsh from UBC and Mr. Lucas from the University of Victoria.

Welcome to both of you. It's great to have folks from B.C. here in person, because otherwise they usually have to get up super early to be on video conference. So it's nice to have you here in Ottawa.

We'll do our usual rounds. We'll have a seven-minute round and then a five-minute round. We do have two hours, so you're actually on the hot seat today because you're the only two witnesses. We'll go as long as there are questions and until we get to the end of our meeting time.

Again thank you for being here and we'll begin with Dr. Walsh.

[Dr. Zach Walsh, Associate Professor, University of British Columbia, As an Individual]

Thanks for inviting me. It's an honour to be here.

Given the relatively brief time I have, I'd like to highlight five points that I think are particularly salient to the estimation of the health risks and dangers of cannabis. My first point provides a broad context for the discussion to follow. I am a clinical psychologist and an addictions researcher with considerable experience conducting research with, and providing treatment to, individuals who struggle with problematic substance use and mental health more broadly.

In light of my expertise in this area, I'd like to focus primarily on the harms and risks of cannabis use as they pertain to psychological and behavioural functioning and well-being. I'm also choosing to focus on psychological and behavioural effects, rather than physical health per se, due to the absence of evidence for meaningful physical health risks and harms associated with cannabis use.

A 1988 ruling by U.S. DEA Chief Administrative Law Judge Francis Young described cannabis as “one of the safest therapeutically active substances known to man”. Considerable subsequent research that has examined the health consequence of cannabis use has not provided evidence to the contrary. Judge Young's statement is, in my opinion, as true today as it was a little more than 25 years ago. In the absence of risks and harms related to physical health, I believe the estimation of risks and harms should focus on psychological health and public health.

To this end, I would like to speak to the state of the science regarding the associations between cannabis use and the negative health outcomes of violence, cognitive functioning, anxiety, and psychosis. Because of the limited time, I'm just going to provide an overview of each of these points, focusing on a few key studies that I've provided to the clerk.

Violence is a major public health concern and a leading cause of injury. A robust literature attests to violence being an important negative consequence of substance use in general, particularly alcohol use. As such, it makes sense to investigate the extent to which cannabis use might also be associated with interpersonal violence. Indeed, the prohibition of cannabis in the early 1900s was fueled in part by the putative role of cannabis in eliciting aggression, and the association between cannabis use and violence has garnered substantial research attention. However, in contrast to the robust literature relating alcohol use to violence, the evidence of an association between cannabis use and violence is not at all clear. The results of extant studies are inconsistent, and many have failed to consider the potential confounding effects of other variables, such as general antisociality and the concurrent use of other substances, most notably alcohol.

Indeed, one of the most prominent theories explaining the association between cannabis use and violence, the general deviance theory, proposes that the apparent association between cannabis use and violence, when it is apparent, can be attributed to general predisposition to rule-breaking and antisociality rather than reflecting any direct effects of cannabis use per se. This proposition is consistent with the findings of laboratory studies of animals that find no association between cannabis intoxication and aggression.

Human studies produce divergent results. Although some studies have found associations between cannabis use and increased risk for violence, many have failed to control for key variables. A recent study that examined temporal association between cannabis use and domestic violence—that is, which came first, the substance use or the violence—found that cannabis use was associated with a reduced risk for violence. Another recent study of male domestic violence perpetrators reported no association between cannabis use and domestic violence after accounting for alcohol use. This later finding is consistent with recent work from our lab, which found that the association between cannabis use and the perpetration of domestic violence was accounted for by alcohol use and antisocial personality features. In sum, there's not strong or consistent support for the proposition that increased violent behaviour should be included among the risks and harms of cannabis use; it should not be.

Interestingly, a very recent U.S. study that examined the effects of medical cannabis legalization on violent crime found that legalizing medical cannabis was associated with decreased rates of violence in the states that did so. Such findings are plausible to the extent that cannabis may serve as a substitute for such other consciousness-altering substances as alcohol or amphetamine, for which more robust associations with violence have been established. However, more research is required to estimate the potential of cannabis to reduce interpersonal violence.

As is the case with research that has examined the association between cannabis and violence, studies that have examined the association between cannabis use and mental functioning have not led to a scientific consensus on the consequences of cannabis use for cognitive performance. While it is clear that for many users acute cannabis intoxication interferes with cognitive processes, such as memory and attention in the hours directly following cannabis ingestion, the longer-term consequences and the stability of any detrimental effects are not clear and appear to depend on a number of other factors.

Specifically, even the acute effects of cannabis intoxication appear to vary considerably from individual to individual, with more profound cognitive effects being experienced by infrequent cannabis users, whereas regular cannabis users appear to develop tolerance to the cognitive interference and associated performance deficits that may accompany cannabis intoxication.

Of greater concern than acute effects of cannabis are the longer-term or residual effects and the reversibility of any cannabis-related cognitive differences following cessation of cannabis use.

A study conducted at Harvard Medical School compared three groups: frequent cannabis users, who had used more than 5,000 times across their lifetime and were still using cannabis regularly; frequent users who had cut down or quit their cannabis use; and non-users. The study found that after a 28-day abstinence period, the three groups did not differ on tests of cognitive functioning.

Similarly, a comprehensive meta-analysis—that's an analysis of several studies wrapped into one—on the non-acute effects of cannabis found a small but discernible residual effect of cannabis use in only two of eight cognitive domains and concluded that, based on the extant data, they “failed to reveal a substantial, systematic effect of long-term, regular cannabis consumption on the neurocognitive functioning of users”. Notably, a recent study of Canadian youth reported better academic performance among those who used both cannabis and tobacco compared with those who used tobacco alone.

In sum, the extant data indicates that whereas acute cannabis intoxication may interfere with response speed, memory, and attention, the evidence does not indicate that substantial, irreversible detrimental effects on mental functioning or on performance of cognitively demanding tasks should be included among the risks and harms of cannabis use. They should not be.

The relationship between cannabis use and psychosis has been the subject of considerable research attention, and several studies have confirmed the existence of an association between cannabis use and psychotic disorders, the most concerning of which is the serious and debilitating condition of schizophrenia. However, the extent to which cannabis use plays a causal role in the development of schizophrenia remains unclear, as does the extent to which cannabis use influences psychoses among those who might not otherwise develop a psychotic disorder. There is, however, evidence that cannabis use may lead to earlier age of onset of schizophrenia among some vulnerable individuals and may also lead to some worse outcomes among those with a history of psychotic disorders.

A compelling argument used to refute the causal association between cannabis use and psychosis is the observation that the substantial rise in the prevalence of cannabis use over the past several decades has not been accompanied by a rise in the incidence of psychotic disorders. However, this important observation does not preclude the possibility that cannabis use might have more subtle effects on the exacerbation of existing psychosis or on lowering the age of onset of full-blown psychotic disorders. In general, as is the case with much of the research on cannabis and mental health outcomes, further research is required to establish causation and to rule out such potentially confounding factors as personality, pre-existing mental health vulnerabilities, and concurrent use of other substances.

Indeed, there is growing evidence that the constituents of cannabis may have opposing effects on the development of psychosis, with THC, one of the active ingredients in cannabis, leading to the development or exacerbation of psychosis, whereas CBD, one of the other main constituents, having anti-psychotic effects. This suggests that individuals at risk of psychosis may use cannabis to relieve symptoms; this may in turn lead to the over-estimation of the causal influence of cannabis use.

These divergent effects of the distinct constituents of cannabis further suggest that the risks associated with cannabis use might vary according to the type of cannabis used, i.e., be related to the relative ratio of THC and CBD.

In summary, although further research is needed and the effects are dependent on a diverse array of other risk factors related to genetics, environmental context, and cannabis varietals, the evidence suggests that cannabis use may confer risk for earlier onset and worse outcomes among the small proportion of the population who may be predisposed to psychosis.

Finally, the association between cannabis and anxiety has been noted in the medical literature for well over a century. Nonetheless, the empirical literature remains equivocal with reports of both anxiety-relieving and anxiety-causing consequences of cannabis use.

Some studies reported a higher prevalence of anxiety disorders among heavier cannabis users and the risk of later development of anxiety disorders among cannabis users. In addition, panic-like responses are among the most common unwelcome side effect of cannabis intoxication, particularly among naive users. In contrast, other studies report decreased depression and anxiety amongst cannabis users, and the relief of anxiety is among the primary reported motives for cannabis use. Cannabis has also been noted for its effectiveness in relieving anxiety that is secondary to other medical conditions, such as chronic pain, HIV/AIDS, and multiple sclerosis.

Results from our lab provide further evidence of the anxiety-relieving rather than anxiety-causing effects of cannabis. Relief of anxiety was among the most commonly reported reasons for using cannabis among Canadian medical cannabis users, and our research with students indicates that frequent cannabis users were less anxious and less sensitive to psychological symptoms of anxiety than were infrequent users and abstainers.

Consistent with the potential anxiety reducing properties of cannabis is the inclusion of post-traumatic stress disorder, PTSD, among the conditions for which medical cannabis is recommended or allowed in several U.S. states. Researchers in the U.S. are now preparing to conduct clinical trials of cannabis for PTSD to help relieve the suffering of war veterans, PTSD being one of the most serious and debilitating of the anxiety disorders.

In summary, research on the association between cannabis use and anxiety is equivocal and extant research does not indicate that the problematic exacerbation of anxiety should be included among the risks of cannabis use. Indeed, further research may establish cannabis or its constituents as treatments for some types of problematic anxiety.

Thank you very much.

[The Vice-Chair, NDP, Libby Davies]

Thank you very much, Dr. Walsh. I did let you go over a bit, because there's only the two of you today and I could see everybody madly taking notes. Thank you very much for your presentation.

We'll begin questions after we've heard Mr. Lucas.

Mr. Lucas, please go ahead.

[Philippe Lucas, Doctoral Candidate, University of Victoria, As an Individual]

Thank you very much, Madame Chair. I just have to ask Dr. Walsh if he wouldn't mind stepping over here and working the French side of my presentation, because I only have so many hands. If we could set the time when I begin that would be great.

Thank you, Madame Chair.

My name is Philippe Lucas. l'm a Ph.D. student in the University of Victoria's social dimensions of health program, a graduate researcher with the Centre for Addictions Research of British Columbia, and vice-president of Patient Research and Services at Tilray, is a federally licensed medical cannabis company located in Nanaimo, B.C.

Today my presentation will explore the impacts of cannabis use on both individuals and society as a whole, with a focus on addiction. So let's begin by answering a crucial question, is cannabis addictive?

Evidence suggests that only about one in ten regular cannabis users develops problematic patterns of use and, as you can see from this chart, studies have found cannabis to be considerably safer and less addictive than many licit and illicit substances, including nicotine, alcohol, and even caffeine. For those who do develop a dependence on cannabis, withdrawal is typically mild and short-lived. According to the DSM-V, the symptoms of cannabis withdrawal include irritability, loss of appetite, and sleeplessness lasting a few days to a few weeks, and the majority of Canadians who give it up do so without the need for formal addiction treatment.

Despite its low potential for abuse, for decades cannabis was touted as a potential gateway or stepping stone to harder drugs; however, both social and clinical research have convincingly debunked the gateway theory.

The Senate Special Committee on Illegal Drugs 2002 report on cannabis concluded that while it may be true that many people who use hard drugs have also used cannabis, the reasons range from social factors such as poverty to the illegal status of cannabis, which ultimately results in the black market control of its distribution. As the Senate discovered, Canadian drug use trends simply do not support the gateway or stepping stone hypothesis, concluding that, and I quote, “...while more than 30% [of Canadians] have used cannabis, less than 4% have used cocaine and less than 1% heroin”.

Additionally, recent evidence suggests that rather than being a gateway to addiction, for some people cannabis has proven to be an exit drug for problematic substance use. A number of studies on both humans and animals have found that the cannabinoid system plays a role in dependence and addiction to both licit and illicit substances. For example, research shows that nicotine cravings can be modulated by the endocannabinoid system, and recent studies suggest that cannabinoid receptors interrupt signaling in the opioid receptor systems, affecting both cravings for opiates and withdrawal severity. Labigalini Jr. et al studied this effect on people with a dependence on crack cocaine, reporting that 68% of the 25 subjects who self-medicated with cannabis in order to reduce cravings were able to give up crack altogether.

Furthermore, research suggests that cannabis use does not interfere with substance abuse treatment. Data from the California outcomes measurement system found that medical cannabis patients fared equal to or better than non-cannabis users in important outcome categories such as treatment completion, criminal justice involvement, and medical concerns. More recently, Scavone et al examined the impact of cannabis use during stabilization on methadone maintenance treatment in 91 patients with a dependence on opiates, finding that opiate withdrawal decreased in patients using cannabis, thereby improving overall methadone treatment adherence and outcomes.

My own research supports these findings. I recently conducted a cross-sectional survey of the subjective impact of medical cannabis on the use of both licit and illicit substances as self-reported by 404 medical cannabis patients, finding that 75% of respondents report substituting cannabis for another substance: 67% use cannabis as a substitute for prescription drugs, 41% as a substitute for alcohol, and 36% as a substitute for illicit substances like crack cocaine and crystal meth.

These findings are further reflected in results from the “Cannabis Access for Medical Purposes Survey”, otherwise known as CAMPS, which is the largest polling of Canadian medical cannabis patients to date. Overall, 86% of CAMPS participants reported using cannabis for at least one other substance: 80% of patients stated they used cannabis as a substitute for prescriptions drugs, 51% as a substitute for alcohol, and 32% used it as a substitute for illicit substances.

Patients who listed a greater number of symptoms were more likely to report cannabis substitution, and interestingly, patients below 30 years old were far more likely to substitute cannabis for prescription drugs, alcohol, and illicit substances than those 50 and over.

In regard to youth, a survey of 67 UBC students aged 17 to 24 that examined cannabis and alcohol use over the last six months found that 71% reported drinking more slowly when using cannabis, 53% reported drinking less when using cannabis, and 34% stated they didn't desire alcohol when using cannabis, with 0% reporting increases in alcohol cravings. This suggests that for some students cannabis is a conscious means of reducing alcohol use.

That's the state of knowledge about cannabis and addiction, but what about the impact of cannabis use on society as a whole? The current government has made crime reduction a central part of its platform, so it may be useful to understand if an increase in the use or social acceptance of cannabis leads to an increase in crime. Interestingly, a new study by Morris et al on crime rates in U.S. states that legalized medical cannabis found that there was actually a net reduction in rates of homicide and assault in medical cannabis states compared to neighbouring jurisdictions.

The authors suggest:

Given the relationship between alcohol and violent crime, it may turn out that substituting marijuana for alcohol leads to minor reductions in violent crimes that can be detected at the state level.

So what are the public health impacts of Canadians using cannabis instead of alcohol, pharmaceuticals, and illicit substances? In light of the alarming rise in addiction to prescription opiates in Canada, a growing body of research suggests that cannabis may prove to be a safe and effective substitute for patients treating chronic pain as well as non-medical opiate users.

Additionally, since the intravenous use of opiates, crack and cocaine, and crystal meth can all lead to the transmission of serious chronic conditions like HIV/AIDs and hepatitis C, evidence suggesting that cannabis might be an effective substitute for these substances can be part of a public health-centred strategy aimed at reducing disease transmission and overdoses from injection drug use. Since alcohol has a far greater social, health, and financial impact on individuals and communities than all illicit substances combined, public policies informed by the growing evidence that cannabis might reduce or even treat alcohol dependence could have a significant impact on overall rates of alcoholism, and consequently on alcohol-related automobile accidents, domestic violence, and violent crime.

To sum up, cannabis is not particularly addictive and 90% of regular users never develop a dependence on it. Furthermore, a growing body of evidence suggests that cannabis, once thought of as a gateway drug to addiction, may ultimately prove to be an exit drug to problematic substance use for some individuals. In light of this research, policies that reduce the penalties associated with cannabis use or regulate legal access by adults could reduce the harms associated with alcohol and problematic substance use on both public health and safety and could even lead to a reduction in violent crime in Canada.

I'd like to end by thanking the House of Commons for inviting me here today, and Tilray, the Centre for Addictions Research of BC, and the University of Victoria for supporting my research.

I look forward to your questions. Thank you, Madam Chair.

[The Vice-Chair, NDP, Libby Davies]

Thank you very much. It was perfectly within the 10 minutes.

We'll begin our first round of questions, which is seven minutes. You may want to put your earpiece in if you don't understand both official languages.

We'll begin with Dr. Morin, for seven minutes.

[Dany Morin, NDP, Chicoutimi—Le Fjord, QC]

Thank you very much, Mr. Chair.

I just want to make sure that everybody can understand French. If not, put your earpiece in and you can program the device in front of you for French.

Sorry, Madam Chair—

[The Vice-Chair, NDP, Libby Davies]

It's okay.

[Dany Morin, NDP, Chicoutimi—Le Fjord, QC]

—I'm going to wait for my witnesses to....

[The Vice-Chair, NDP, Libby Davies]

I think Philippe was—

[Dany Morin, NDP, Chicoutimi—Le Fjord, QC]

I want to thank the two witnesses for meeting with us today. The information they have provided is fairly new, as it has not been brought to the committee's attention until now. I appreciate the fact that the information is coming from two members of the scientific community.

Since the beginning of the study, it has been pointed out that scientific research on this issue is lacking—and you also mentioned that—either when it comes to the health benefits or the health risks involved. The Canadian government has had a medical marijuana program for several years. However, the medical use of marijuana is not supported by scientific evidence. That is why I am very grateful for your personal and collective contributions.

My first question is about the program I mentioned.

Health Canada published a document titled Information for Health Care Professionals, which outlines the scientific knowledge on the use of cannabis and cannabinoids in the treatment of a host of diseases. The document also discusses adverse effects.

Do you think this document does a good job of taking into account the scientific literature on marijuana's potential therapeutic uses and side effects?

[Dr. Zach Walsh]

I think the directions for health providers is quite a good document in general. It's certainly fairly comprehensive. I was actually quite impressed with that document, yes.

[Philippe Lucas]

Like any document, before it appears, it's a little behind the times. It doesn't capture the last three or four years of research, and clearly it focuses more on potential harms than on actual medical efficacy.

The amount of science that's being presented now on the potential benefits of medical cannabis is remarkable. The chief areas of exploration include cannabis and cannabinoids in the treatment of cancer; in the treatment of mental health issues, as Dr. Walsh has discussed; in the treatment of dementia and Alzheimer's, as well as a number of physical conditions.

There is no doubt that the last 70 years of prohibition have significantly impacted the amount of research that's been available to do in North America and throughout the world. But as those research restrictions seem to be falling away and as we are able to work with more patients throughout Canada and around the world within scientific contexts, we are seeing a growing amount of opportunities to conduct research on the therapeutic potential of cannabis.

It's interesting to note that Dr. Walsh mentioned post-traumatic stress disorder as one of the treatment opportunities for cannabis. I think we can all agree that treating our soldiers, police officers, and correctional workers who have suffered trauma is one of the key goals and challenges of our public health system.

Right now Veterans Affairs Canada pays for the cost of medical cannabis for veterans who need it for the treatment of post-traumatic stress disorder. It's one of the only patient groups in Canada that gets cannabis paid for, and I think it's a step in the right direction to cover the cost of cannabis for those soldiers who've been affected by trauma while serving their country.

[Dany Morin, NDP, Chicoutimi—Le Fjord, QC]

Last week, Andra Smith, another scientist, told us about her own research on cannabis. She said it may be beneficial for Health Canada to carry out or sponsor more research projects in order to flesh out the file on the medical use of marijuana and on the federal program. I hope that research will be undertaken soon.

When Health Canada does conduct or sponsor that type of research, should it prioritize any specific areas? Those areas could include pain management, nausea, vomiting and epilepsy. Do you think the studies on the medical use of marijuana should be specific or more general?

[Dr. Zach Walsh]

We need broad-based research. The conditions you mentioned are certainly good starting points. In our research with Canadian medical cannabis users, we found that a large proportion are also using cannabisto treat anxiety both on its own and in relation to their illness, and to assist with sleep, in addition to some of those areas that you mentioned.

For anxiety and sleep, many Canadians use prescription medications and over-the-counter medications, and I believe we need studies to compare the side-by-side efficacy of cannabis with those widely used medications, because they have their own set of benefits but also their own set of risks, particularly the common sleeping medications and benzodiazepines. One area of particular importance would be a comparison of cannabis to those sleep and anti-anxiety medications.

[Philippe Lucas]

I think that we've mentioned some of the conditions that I think are the most promising and the most challenging to treat that we can look at with cannabis. There is ongoing cancer research around the world including on its relieving effects and the anti-tumourific and anti-carcinogenic effects of cannabis and cannabinoids, including tumour reduction in glioma patients, breast cancer patients, and breast cancer cell lines. I think those are very promising areas that deserve more attention. I don't know many families that haven't been affected by cancer, so personally I think that would be a promising direction.

There is also growing interest right now in using non-psychoactive forms of cannabis with higher CBD, or cannabidiol, in the treatment of childhood seizure disorders. Some of you may be aware of circumstances where there are parents right now who are seeking access to cannabis supplies that are low in THC, which is the psychoactive in cannabis, and high in CBD to treat seizure disorders of children as young as two who are having up to 100 seizures a day and whose lives are literally threatened by these seizures. So far the findings have been very promising, very anecdotal, and not very scientific yet. But I think when it comes to parents who are desperate to save their kids' lives, that's an area that we absolutely need to look at and move forward in.

Also we mentioned post-traumatic stress disorder earlier. My personal research at the University of Victoria, my research interest, is looking at medical cannabis patients' patterns of use. We still don't know the most basic science around how Canadian patients are using medical cannabis. We have 50,000 Canadians right now who are using medical marijuana. I can't tell you, for example, how much the average patient using it for MS uses it per day. I can't tell you their strain preference, if they have a preference of one strain or another. We don't have even that kind of basic information, so that's part of my Ph.D. work right now, looking at a thousand Canadian patients and following their use over a year's time to gather some of that basic information.

[The Vice-Chair, NDP, Libby Davies]

I think we'll wrap it there and maybe come back to the subject because we're over time now.

Now we'll turn to Mr. Wilks.

[David Wilks, Conservative, Kootenay—Columbia, BC]

Thank you very much, Madame Chair.

Thank you to the witnesses for being here today.

I want to continue with your point about the 50,000 marijuana users through the medical process and that we've never really monitored what they do. I wonder if you could talk a little bit more about that, because it's a concern to me that we introduce a substance that we don't control, but then we don't monitor it either. We claim that it has successes, but we can't prove it. So I appreciate what you said today, but the reality is that we can't prove anything right now. Talk a little more about how we go about proving all of this, because there is no way of doing it.

[Philippe Lucas]

The fact is that there are a lot of treatment modalities around medical cannabis that have been proven through clinical trials. We have a study—

[David Wilks, Conservative, Kootenay—Columbia, BC]

But what about the 50,000 that we're talking about?

[Philippe Lucas]

Well, there is very little monitoring going on there, and I've suggested in the past at consultations with Health Canada that what we really need is a pharmaco-vigilance program around the medical cannabis program that would allow the tracking of patients.

I had a recent conversation with Dr. Mark Ware, who is president of the Canadian Consortium for the Investigation of Cannabinoids, and I understand that he and the Quebec government have an agreement to track all Quebec patients in terms of looking at their use through their physicians. That is going to be ongoing and it is something that we can certainly look at down the road as more of a national study.

Now, it's not unusual at all for us to have thousands of Canadians on different prescription drugs without doing active monitoring of what's happening with each patient.

[David Wilks, Conservative, Kootenay—Columbia, BC]

But I guess the difference between cannabis/marijuana and the other drug is that every other drug is regulated, and cannabis is not.

[Philippe Lucas]

Well, cannabis is tightly regulated, that's why we have an MMPR program. Access to cannabis is much more challenging than access to any commonly, potentially more dangerous pharmaceuticals.

[David Wilks, Conservative, Kootenay—Columbia, BC]

So what is the argument with regards to the synthetic models that Canada provides to patients? There are two regulated and one oral spray as well. Speak a little bit about that compared to the ingestion of smoking marijuana.

[Philippe Lucas]

I'd be happy to. As you say, Marinol, Cesamet, and Sativex are the commonly prescribed alternatives to raw cannabis. Marinol and Cesamet are single agents. One of them is an actual THC molecule, and the other one is a synthetic THC mimic. All of the research that's been conducted looking at single agent mimics have found them to be less effective in terms of treatment modalities than whole-plant cannabis. What scientists call the synergistic effect seems to be one of the important factors in the efficacy of whole-plant cannabis.

Now, Sativex is an oral mucosal spray that is a whole plant cannabis product. I think that it is much more promising than Marinol and Cesamet, but I still think that for most patients it's going to be inaccessible because of cost issues—it's a very expensive product. It's the equivalent of having a single strain of cannabis available to all Canadians. What we've found in research is that not all strains are effective in all conditions under all circumstances, so having a variety of cannabis strains, which is what's happening under the new MMPR, has made a big difference for cannabis patients.

[David Wilks, Conservative, Kootenay—Columbia, BC]

One of my concerns with the program has always been that we don't have visible control for all Canadians to see what THC levels are. We all recognize that over the years the THC levels have increased, from the 1970s to now. In fact, there are some THC levels that are relatively high. I would suggest the average THC level is probably between 10% and 15%, but there are some that are much higher.

My concern is that we don't have any way of controlling that from of the perspective of outside of the MMRP. We still have the old system in place, as you know. I would suspect that a lot of those 50,000 people whom you refer to are not purchasing it through what we would call the MMRP program, but are getting it through their own sources, which is somewhat concerning to me. How do we control that?