Evidence of meeting #27 for Health in the 41st Parliament, 2nd session. (The original version is on Parliament’s site, as are the minutes.) The winning word was effects.
A recording is available from Parliament.
NDP
Claude Gravelle NDP Nickel Belt, ON
Thank you, Madam Chair.
Mr. Lucas, you said that 80% of cannabis is used as a substitute for prescription drugs.
Can you give us an example of the drugs that cannabis can be substituted for? Can you also tell us what the cost effect is on the Canadian health care system?
Doctoral Candidate, University of Victoria, As an Individual
Absolutely.
The most common substitution is for drugs involving chronic pain, so pharmaceutical opiates, and typically drugs that are pain relievers. Of course, the pharmaceutical opiates are attributed to the fastest-rising rate of addiction in Canada, with the associated fastest-rising rate of morbidity, which is disease and death—mortality. I think anything that allows us and physicians an alternative, to give them another tool than using prescription opiates in the treatment of chronic pain, can be very beneficial.
There has been no study to date to look at the impact on the public health system that medical cannabis users have or might have on the health system. That is part of my Ph.D. research right now. I'm doing an open cohort study of 90 patients who start using medical cannabis. I'm going to focus on post-traumatic stress disorder as a primary condition, and I'm going to track them over periods of time to see how medical cannabis use affects their use of other substances, and subject that to an economic analysis as well.
What I can tell you is that there has been a study by a large Dutch insurer—Holland also has a medical marijuana program—that decided to cover the cost of medical marijuana. Based on the results of their own internal study, they found that medical cannabis users, compared with patients with similar conditions, were doing better and had fewer ER visits, fewer doctor visits, and were using fewer pharmaceuticals.
NDP
Claude Gravelle NDP Nickel Belt, ON
Thank you very much for that.
My colleague Mr. Wilks was concerned a little about the safety of cannabis a while ago, and he said that every other drug is regulated. That may be true, but every other drug that is regulated is not necessarily safe. Have there been a lot of regulated drugs that have caused harm and that have been taken off the market because they weren't safe? In other words, because you're regulated doesn't mean it's necessarily safe.
Doctoral Candidate, University of Victoria, As an Individual
I'm unfortunately affected by hepatitis C, which I got in 1982 through the tainted blood system here in Ontario. I can tell you that one of the main reasons for hospitalization associated with liver disease is actually the overuse of Tylenol.
You don't need to just look at prescription drug use to find problems with our current use of pharmaceuticals. I believe I read a study recently that showed that 23% of hospitalizations in the United States are caused by the misuse, abuse, or overuse of prescription drugs. It ends up being the number one cause of hospitalizations in the entire United States.
There's no doubt in my mind that there's currently a lot of legal, either prescription or over-the-counter, drugs, which unfortunately lead to a lot of health problems in Canada.
Doctoral Candidate, University of Victoria, As an Individual
No.
As I've stated, the evidence suggests that people of higher education and higher rank tend to use cannabis as well. Unfortunately, our drug war focuses on 15-year-old to 25-year-old males. They're the majority target of our current enforcement policies.
When I've done studies of medical cannabis users at medical cannabis dispensaries, we tend to find that the average user is above 40 years old. That takes us well out of youth use.
It's also worth mentioning—and I completely agree, and I think we can all agree here in this room—that cannabis is not a panacea; it's not without health consequences. My concern, as someone who studies public health and cannabis and addiction, is whether criminalization is an effective public health tool in assisting people in dealing with potential problems to self or society.
NDP
Claude Gravelle NDP Nickel Belt, ON
Thank you.
In 2006, you helped to update a book, which I want to quote from. I'm talking about cancer right now:
Cannabis has been found to help cancer patients with the symptoms that usually accompany cancer such as pain, nausea, wasting, and loss of appetite. Notably, in a meta-analysis of 30 clinical studies on the therapeutic use of cannabis for chemotherapy-induced nausea and vomiting...proved superior to modern anti-emetics. Additionally, patients showed a clear preference for cannabinoids as anti-emetic medication over conventional drugs, when receiving chemotherapy.
Can you comment on that please?
Doctoral Candidate, University of Victoria, As an Individual
Sure. I think the evidence is starting to grow that cannabis can be used safely and effectively. I see it as one of the many tools that our medical system can benefit from. Until the 1930s it was part of the North American pharmacopoeia, and physicians were using cannabis in a lot of different preparations. We are now rediscovering its therapeutic potential through scientific research.
NDP
The Vice-Chair NDP Libby Davies
Okay, we'll leave it at that. Thank you very much, Mr. Gravelle.
We'll now turn to Dr. Lunney.
Conservative
James Lunney Conservative Nanaimo—Alberni, BC
Thank you very much, Madam Chair. It is nice to see you in the chair today.
Thanks, witnesses, for being with us today.
I want to refer back to one of the earlier witnesses as well, Dr. Andra Smith. She is a neuroscientist. This is referring to the Ottawa pre-natal study. Would you be familiar with that work, using functional MRI?
They follow these subjects right from birth through their adolescent years, but they quantify some very significant changes in blood flow with people, referring to the executive functions that are impaired in marijuana users and the delayed cognitive response, reasoning power, problem-solving, and decision-making, particularly in the case of adolescents. The younger they are when they start and the heavier the use, the greater the impairment.
It seems to me that would be of real concern, with Canada's youth being one of the highest user populations in the world. It speaks to the productivity of our country, which is important to some of us at the table here. We want citizens who are able to perform higher cognitive-function activities later in life. I wonder whether it is of concern to you that in fact the fMRI evidence shows that it is delaying myelination in the prefrontal cortex and shifting activities to the limbic system, where decisions are made more on an emotional basis; that people performing these tasks are actually taking longer to solve simple problems, and that this therefore perhaps leads to the anxiety that we're referring to.
I wonder whether you have any comment on that part of the scientific literature that is out there and those concerns?
Associate Professor, University of British Columbia, As an Individual
I'm familiar with the findings of acute cognitive effects of cannabis intoxication. I'm not familiar with the Ottawa pre-natal study that you refer to, but I am quite familiar with the literature on the cognitive effects of cannabis.
My sense of the literature is that the effects are generally reversible following cessation of cannabis use and that they vary according to the user's familiarity with cannabis, so that when cannabis is administered to relatively naïve users we see more profound deficits and that with regular users there is tolerance of most of the cognitive effects.
Of course, I'm highly concerned about the productivity of our young people. That is what I have devoted much of my life to fostering.
Doctoral Candidate, University of Victoria, As an Individual
If I could add a bit to that.
I think you're absolutely right that we should all be concerned about youth trends of use. I think we need to be conscious of this. In B.C., for example, about 70% of graduating high school students will have tried cannabis, and only 50% will have tried tobacco. We actually have a higher use—
Doctoral Candidate, University of Victoria, As an Individual
About 70% will have tried cannabis and about 50% will have tried tobacco. In fact, the trends are declining right now.
It's interesting that using a public health-centred campaign and honest education, we have reduced tobacco rates without having to criminalize anyone or criminalizing our youth. But we've had to do that, and we're having no success is reducing youth use of cannabis.
It is also worth mentioning that U.S. states that have legalized medical marijuana are now finding a decline in youth use of marijuana, which is interesting. We find the same thing in Holland as well.
Conservative
James Lunney Conservative Nanaimo—Alberni, BC
Thank you.
Well, in long-term studies, actually—I'm talking about the Neeson study in New Zealand.... They reported on decreased IQ, school dropouts, increased attention span problems, and again the impairment of higher cognitive and executive functionings. That's a significant increased risk to youth. There is also the increased risk of MVAs, which of course we would be concerned about for young people.
I want to make reference to the harmful effects on the lungs that were mentioned here by Ph.D. Kevin Sabet, showing an increased risk of bronchitis, cough, and phlegm production. He claims that there are 50% to 70% more carcinogenic hydrocarbons than in tobacco use. You talk about there being no significantly established health risks; I wonder how you respond to 50% to 70% more carcinogenic hydrocarbons. He went on to say that marijuana smoke contains an enzyme that converts hydrocarbons into a cancer-causing form, something on which he didn't actually elaborate scientifically.
I wonder how you relate those potentially cancer-causing risks for the lungs—I think I heard one of you suggest that it may be a cancer treatment, which I find quite astounding—and furthermore the contention that persistent and heavy use among adolescents reduces IQ by six to eight points. That would be a concern, I would think, to most people wanting to see a young generation grow up to become highly productive adults.
Associate Professor, University of British Columbia, As an Individual
Certainly, and I don't think anyone would advocate cannabis use for young people. The study that you referred to, the Dunedin study, is one of the studies where substantial concerns have been raised about confounds. With the criminalization of cannabis, we see people who are more likely to violate all kinds of rules using cannabis. So it's not the effects of cannabis per se, but rather confounds related to socio-economic status or other personality factors related to rule-breaking and anti-sociality that may account for some of those IQ changes. So the Dunedin study, I think, is problematic and there have been publications to that effect.
Doctoral Candidate, University of Victoria, As an Individual
I mentioned the Tashkin study.
Doctoral Candidate, University of Victoria, As an Individual
I've submitted it to you, so you can look at the Tashkin study.
NDP
The Vice-Chair NDP Libby Davies
Thank you very much.
Thank you, Dr. Lunney.
We'll now go to Ms. Jones for five minutes.
Liberal
Yvonne Jones Liberal Labrador, NL
Thank you, Ms. Davies.
And thank you both for your presentations this morning. My apologies, but I was at the mercy of the airlines so I arrived a little past the due time.
However, I do have a couple of questions, and my apologies to the committee if they're somewhat repetitious of what's already gone on.
First of all, I'm just going through the note here. It states that cannabis use would relieve secondary anxieties. Can this lead to a decrease in prescription drugs such as anti-depressants and those kinds of medications?
Associate Professor, University of British Columbia, As an Individual
Well, I think the good research remains to be done as far as the side-by-side efficacy of cannabis versus other anti-anxiety medications is concerned, but our reports from medical users and non-medical users indicate that cannabis does reduce their anxiety. It's one of the primary reasons that people use it. Amongst people with chronic and severe illness, they report high levels of using cannabis to deal with anxiety. We need to compare the side-effect profiles of cannabis to the other substances that are widely prescribed, the anti-anxiety medications, that also have more severe side effects in many ways than cannabis. We need a side-by-side trial of those two to say which is more effective, which has more palatable side effects, but the potential is certainly there, I believe.
Doctoral Candidate, University of Victoria, As an Individual
What I would add to that—and I think you missed this part of the discussion—is that currently Veterans Affairs pays for the cost of medical cannabis to veterans who are suffering from PTSD. One of the main symptoms of PTSD is high levels of anxiety; depression was mentioned earlier as well. We have very few good, effective tools to treat PTSD here in Canada or around the world. Those with PTSD are the only patient group I'm aware of in Canada that have their medical cannabis covered by the federal government.
There's an increased interest in research around the treatment of post-traumatic stress disorder using cannabis. There's a study that's been approved recently by the U.S. government, and a Canadian arm of that study will potentially start in the next few years as well.
Liberal
Yvonne Jones Liberal Labrador, NL
Is anyone doing any of the research around that? I guess my question would be for Dr. Walsh. You were saying that you need to do a side-by-side examination looking at this. Has that been done? Is anyone doing that in the medical or research community in Canada right now?
Associate Professor, University of British Columbia, As an Individual
Unfortunately, that's not being done, to my knowledge. One thing you'll see running through the testimony and the research on medical cannabis is that it's incredibly difficult to conduct studies using cannabis, either administering it or clinical trials. There's so much research that remains to be done.