Evidence of meeting #24 for Health in the 41st Parliament, 2nd Session. (The original version is on Parliament’s site, as are the minutes.) The winning word was alcohol.

A recording is available from Parliament.

On the agenda

MPs speaking

Also speaking

Hilary Geller  Assistant Deputy Minister, Healthy Environments and Consumer Safety Branch, Department of Health
Robert Ianiro  Director General, Controlled Substances and Tobacco Directorate, Healthy Environments and Consumer Safety Branch, Department of Health
Hanan Abramovici  Senior Scientific Information Officer, Office of Research and Surveillance, Department of Health
Meldon Kahan  Medical Director, Women's College Hospital, As an Individual
Harold Kalant  University of Toronto, As an Individual

9:45 a.m.

Assistant Deputy Minister, Healthy Environments and Consumer Safety Branch, Department of Health

Hilary Geller

I don't think so. No, there isn't.

9:45 a.m.

Conservative

David Wilks Conservative Kootenay—Columbia, BC

Pardon me?

9:45 a.m.

Assistant Deputy Minister, Healthy Environments and Consumer Safety Branch, Department of Health

Hilary Geller

No, there is not.

9:45 a.m.

Conservative

David Wilks Conservative Kootenay—Columbia, BC

Thank you.

Those are all the questions I have.

9:45 a.m.

Conservative

The Chair Conservative Ben Lobb

Thank you.

According to my BlackBerry, it is a quarter to, so we'll suspend for a couple of minutes and have our other witnesses get tuned up and ready to go.

I thank these witnesses who took the time to be here this morning.

9:45 a.m.

Conservative

The Chair Conservative Ben Lobb

We're back and starting the meeting up again. We have two guests here for the second hour, Harold Kalant—forgive me if my pronunciation is incorrect—and Meldon Kahan.

I think Dr. Kahan testified during our last study as well. We'll get him to go first because he's on video conference, and we want to make sure, while the technology's working, that we get his input and then we'll turn it over to Mr. Kalant.

Dr. Kahan, you have 10 minutes or less. Carry on.

9:50 a.m.

Dr. Meldon Kahan Medical Director, Women's College Hospital, As an Individual

Thank you, Mr. Chairman and members of the committee.

I am currently medical director of the substance use service at Women's College Hospital in Toronto, and an associate professor in the department of family medicine. I would like to acknowledge my colleagues Sheryl Spithoff, Anita Srivastava, Suzanne Turner, and Sharon Cirone. Their work on cannabis has formed the basis for this talk.

I will begin by thanking the committee for undertaking this study because cannabis use in Canada is an extremely important public health issue. A recent UNICEF study found that Canadian teens aged 11 to 15 are the highest users of cannabis in the western world. An estimated 28% have used cannabis at least once in the past year. The 2011 Canadian alcohol and drug use monitoring survey study on youth aged 15 to 24 reported that 22% of adolescent males and 10% of females are daily or weekly users.

I'll now briefly summarize the major health effects of cannabis.

Cognitive effects—daily smokers experience impairment in attention, psychomotor function, and recall. Chronic cannabis use is associated with persistent neuropsychological deficits, even after a period of abstinence. Since the long-term studies are observational, causality cannot be established.

Cannabis use disorder—a review by Professor Kalant estimated that 7% to 10% of regular smokers meet criteria for cannabis dependence. Cannabis use disorder can have a devastating impact on an individual's work and school performance, social relationships, mood, and quality of life.

Psychosis is another major problem with cannabis. Observational studies have demonstrated an association between cannabis use in adolescence and persistent psychosis. Large cohort studies have demonstrated that cannabis use often precedes the development of psychosis, suggesting that it is an independent risk factor. The risk increases with the dose of cannabis smoked.

Anxiety—although a causal relationship has not been confirmed, there is a strong relationship between cannabis use and anxiety and mood disorders as well as suicidal ideation. Acute cannabis use can trigger anxiety and panic attacks.

Cancer—while previous studies have had conflicting results, a recent long-term 40-year cohort study of 50,000 males found that regular cannabis smoking was associated with a twofold risk of lung cancer, after controlling for cigarette smoking and other risk factors.

Cardiovascular disease—cannabis smoking causes acute physiological effects including elevations in blood pressure and heart rate and blood vessel constriction. There have been case reports of young people suffering heart attacks and strokes shortly after smoking cannabis.

Respiratory disease—although it is difficult to control for the confounding effects of tobacco smoke, evidence suggests that heavy cannabis smoking may be an independent risk factor for chronic obstructive lung disease.

I will now discuss groups at high risk for cannabis-related problems.

Youth who smoke cannabis appear to be at greater risk than older adults for cannabis-related harms. Cohort studies have found that cannabis use in adolescence is associated with criminal activity, suicidal ideation, use of other drugs, and poor school and work performance. Cannabis use disorder may be considerably more common among young smokers than older adults. In a prospective study, 30% of youth aged 14 to 24 reported at least one symptom of cannabis use disorder. Adolescent smokers also appear to be at increased risk for persistent and long-term cognitive impairment, possibly because cannabis may induce persistent structural changes in the developing brain.

As for cannabis and driving, cannabis use prior to driving is a risk factor for motor vehicle accidents. Experimental studies have shown that cannabis impairs critical driving skills such as reaction time. Combining alcohol with cannabis increases the risk of motor vehicle accidents to a greater extent than if either drug is used alone.

Finally, regarding pregnancy, preliminary evidence links cannabis use during pregnancy to subtle neurodevelopmental abnormalities in infants, and cannabis can be classified as a teratogen. Cannabis enters the breast milk, and breastfeeding is contraindicated in cannabis smokers.

So why do so many Canadians smoke marijuana, given the harms?

Canadians appear to view cannabis as a harmless herb, and this may be why our per capita use is so high. In a survey of adults in three countries, Canadians were more likely to view cannabis as harmless, and were more likely to have tried cannabis, than were adults in Sweden or Finland.

Public perception of risk correlates with the level of use. An American survey found that the percentage of senior high school students who believe that regular marijuana smoking is harmful dropped from over 70%, in 1993, to 40%, in 2013, while the percentage of high school seniors who smoked daily rose from 2.4% to 6.5% during that time period.

What should be done?

I believe that the first step is to prevent the unintended harms caused by the new medical marijuana regulations that allow physicians to prescribe dried cannabis. This will enhance the public's perception that marijuana is not only harmless but therapeutic. After all, if Health Canada allows marijuana to be prescribed by physicians, it must be a safe and effective medicine.

The evidence suggests otherwise. Smoked cannabis has negligible therapeutic benefits. Pharmaceutical cannabinoids are far safer and at least as effective, and prescribing marijuana will increase diversion and cannabis-related harms.

I will discuss each of these points in turn.

The evidence in support of smoked cannabis is very weak. To date, five control trials have examined smoked cannabis in the treatment of chronic pain. The trials found that it was superior to a placebo for neuropathic pain, but the trials were small and only lasted between one to 15 days. Most people who smoke cannabis for medical reasons do not have severe neuropathic pain, but have conditions commonly seen in primary care, such as fibromyalgia or low back pain. Numerous safe and effective treatments are available for these conditions. Furthermore, pharmaceutical cannabinoids are far safer and have greater evidence of benefit than smoked cannabis.

Two cannabinoids are available in Canada: nabilone or Cesamet; and Sativex, an oral spray that contains a mixture of THC and cannabidiol. These and other oral cannabinoids have far greater evidence of efficacy. The studies have been much longer, and comparisons have included not just placebos but other analgesics. There is preliminary evidence that oral cannabinoids cause better pain relief than smoked cannabis. Furthermore, oral cannabinoids have fewer euphoric and cognitive effects than smoked cannabis, cause less impairment in driving skills, and are associated with low rates of misuse.

Widespread cannabis prescribing by physicians will increase the social and psychiatric harms of cannabis.

Relative to other pain patients in primary care, a higher proportion of medical marijuana users are younger males with mental health problems or substance use disorders. Prescribing cannabis to these high-risk patients may adversely affect their work and school performance, worsen their anxiety and substance use disorders, and increase their risk of motor vehicle accidents.

Furthermore, it may contribute to the illicit drug trade. In a study of adolescents attending an addiction treatment program in the U.S., 47% reported using marijuana supplied to them by a registered medical marijuana patient.

How do we reduce the impact of the new regulations? The most urgent step is for a credible national medical organization, such as the College of Family Physicians of Canada, to develop evidence-based guidelines for prescribing smoked cannabis. Guidelines will give physicians solid grounds on which to make prescribing decisions. Physicians are facing a deluge of requests to prescribe cannabis, and guidelines will give them the support they need to refuse to prescribe cannabis when medically unnecessary or unsafe.

A related step is to limit the dose and THC concentration of medical cannabis. Distributors are selling cannabis strains with THC concentrations of up to 30% or higher, and Health Canada allows physicians to prescribe up to five grams a day. This dose and this concentration are both dangerous and excessive. The amount needed to control chronic pain is probably no more than 400 milligrams of 9% THC cannabis, or one puff four times a day.

I also believe that the provincial medical colleges should regulate the medical cannabinoid clinics that are being established in Toronto, Vancouver, and probably other cities. Although it is too early to say, I am concerned that the physicians in these clinics will prescribe cannabis to large numbers of patients, as has happened in the U.S. The colleges should ensure that cannabinoid clinics conduct comprehensive patient assessments, have explicit and evidence-based prescribing policies, and do not have any financial conflicts of interest, such as charging patient fees or investment in cannabis companies.

Beyond medical marijuana, public health organizations need to conduct public health campaigns to counter the prevailing myth that cannabis is harmless and therapeutic. Physicians, nurse practitioners, and other primary care providers have an essential role in any public health initiative. Evidence indicates that adolescents are open to advice from their physician on substance use. Primary care providers should regularly ask all patients about cannabis use and should educate them on the risks.

Patients with cannabis-related problems should be offered advice and counselling and referral to addiction services if they are unable to quit or reduce their use. There is strong evidence that primary health care providers' interventions for alcohol, tobacco, and opioid problems are effective. It seems likely that the same will hold true for cannabis problems, although research on this is in its early stages.

Primary health care is the only realistic way to reach the large numbers of patients who smoke cannabis and the large numbers who are at risk for cannabis-related harms.

Thank you.

10 a.m.

Conservative

The Chair Conservative Ben Lobb

Thank you very much.

Next up is Mr. Kalant.

Go ahead, sir, for 10 minutes.

10 a.m.

Prof. Harold Kalant University of Toronto, As an Individual

I thank the chair and members of the Standing Committee on Health for their invitation to present a few facts and interpretations on the topic of marijuana and health. My remarks will give special reference to young users.

Marijuana is not the most dangerous of drugs. There are no proven deaths attributable to overdose, and millions of people have used it in small doses and on infrequent occasions with no obvious adverse effects. However, this has given rise to a widespread but erroneous belief that marijuana is safe or harmless.

There is no such thing as a harmless drug. Everything with pharmacological action has the ability to produce harm, depending on the amount used, how often, for how long, by whom, and under what circumstances. Not surprisingly, the harmful effects of marijuana are most often found in heavier users and those with greater vulnerability.

Among those who begin to use marijuana as adults, the most common adverse effects include chronic inflammatory changes in the respiratory system, poor memory, poor work performance in activities requiring mental and physical skills, driving accidents, and addiction. The physical and mental effects usually recover on cessation of use.

However, adolescents and young adult users of marijuana greatly outnumber mature adult users. Young beginners, those who begin use as early as 12 or 13 years, are much more vulnerable to harmful effects and are, therefore, at greater risk. In those with a family history indicative of a genetic risk for schizophrenia, cannabis can precipitate overt clinical psychosis, and in those who have been treated, it increases the risk of relapse and of a difficult clinical course, with poorer results of treatment.

Less dramatic but of much wider application is the fact that the developing brain is more susceptible to the deleterious effects of cannabis. It has an inhibitory effect on the development of connections between parts of the brain involved in higher mental functions. This has been demonstrated in animal studies by histological examination of brain tissue, and in humans by brain imaging studies, showing thinning of relevant areas of the brain cortex in affected users and differences in regional blood flow and electrical activity of such areas. These alterations give rise to problems in such functions as memory, learning, reasoning, and problem solving, which are collectively referred to as “executive functions”.

Our laboratory was the first to show that animals treated before puberty, before reproductive age, with marijuana extract for a month, and then left without treatment for three months to allow complete elimination of the drug, showed long-lasting, apparently permanent impairments to learning. In the laboratory rat, I would point out, three months without the drug is equivalent to about nine years in humans, as a fraction of life expectancy. So these animals were indeed, long-term, free of the drug itself but still showed residual mental effects. Other groups have subsequently confirmed and extended these findings.

Two of the most striking demonstrations of long-lasting effects in humans have come from the Ottawa Prenatal Prospective Study and the Dunedin, New Zealand, birth cohort study.

The OPPS, the Ottawa study, followed groups of offspring of mothers who smoked cannabis during pregnancy in comparison with those of mothers who smoked tobacco or did not smoke at all. Those born of mothers who smoked cannabis showed only minor physical effects at birth that recovered fully during the first post-natal year, but when they reached school age, they showed mental effects that persisted throughout their growth and development and into their adult years. These were minor changes but sufficient to affect the educational attainments of the children.

The Dunedin study followed 1,037 individuals born in Dunedin during 1972-73, with repeated interviews and examinations at intervals of two or three years throughout childhood, before any of the children had started using cannabis, and again at intervals, after they had begun—that is, those who had begun—up to the age of 38 years, most recently.

Those who never acquired a habit of using cannabis showed a small increase in intelligence quotient at 38 years, compared to 13 years, but those who began to use it regularly showed losses in intellectual function that were greater the greater the amount of their use and the earlier the age at which they started.

These losses affected at least five different areas of mental functioning, and were shown not to be due to residual cannabis in the body, not to fewer years of schooling and not to pre-existing mental problems before cannabis use began. As well, they were largely clustered among those who had started use at the youngest ages. Those who began at later ages and ceased using cannabis recovered fully, but in those who started when youngest, cessation of use was not followed by full recovery. These mental effects resulted in more school dropout, poorer social adjustment, and a greater risk of depression later.

Adolescents using cannabis have also been involved in a growing number of motor vehicle accidents as drivers. Culpability analyses point to the cannabis-using drivers as the ones responsible for the accidents, and of course this is obviously the case in single-vehicle accidents. This appears to be due in part to their belief that cannabis does not impair their driving ability, and in part to their knowledge that there's no analytical test for cannabis comparable to roadside breath tests for alcohol, so they feel they are less likely to be detected.

Finally, the risk of addiction is greater in young users of cannabis than in older ones. One study found that whereas the risk of addiction in regular users in general is about 10%, among adolescent regular users it is about 16%.

In conclusion, the use of cannabis for pleasure comes at a cost, and society must ponder whether the pleasure is worth the cost. Sound policy should be based on thorough, comprehensive, and well-researched cost-benefit analyses. The use of criminal sanctions against individuals possessing small amounts for personal use in my view does not benefit society, but society as a whole must give careful thought to changes in policy that could increase the number and severity of health problems caused by use by its more vulnerable members, which, as I have pointed out, means its younger users.

I would like to add, in response to the questions that a number of people asked earlier in this session, that the cost-benefit analysis of medical use is a quite different matter from the cost-benefit use of non-medical use. In medical use you balance the improvement in health and the importance of that improvement in health relative to the harms that may be caused by the dosage used for health purposes, which, as Dr. Kahan has pointed out, should typically be considerably less than the doses employed by regular users for non-medical purposes.

In contrast, for non-medical use, the benefits are not improvements in health and social function but temporary benefits in how one feels. If one is euphoric, one likes it and wants to do more. That's fine, but then the question is whether that pleasure is worth the costs of the damage caused by the heavier doses that non-medical users tend to employ.

Thank you.

10:10 a.m.

Conservative

The Chair Conservative Ben Lobb

Thank you very much.

We'll begin our seven-minute round with Ms. Sitsabaiesan.

10:10 a.m.

NDP

Rathika Sitsabaiesan NDP Scarborough—Rouge River, ON

Thank you, Mr. Chair.

Thank you to both of our witnesses who are here with us today.

First, to Mr. Kalant, I know that you've been here before, but I'm new to this committee and I'm unaware of your background. It just says here that you are from the University of Toronto.

Is your research based specifically on cannabis and health effects? Is that what your research is based on?

10:10 a.m.

University of Toronto, As an Individual

Prof. Harold Kalant

I should explain that I'm a professor of pharmacology in the faculty of medicine at the University of Toronto. I was director of biological and behavioural research at the Addiction Research Foundation of Ontario, which is now part of the Centre for Addiction and Mental Health. My research since 1959 has been largely on alcohol and cannabis.

10:10 a.m.

NDP

Rathika Sitsabaiesan NDP Scarborough—Rouge River, ON

Okay, thank you.

It's great that you have this alcohol background as well. I know this study is about the health risks and harms of marijuana, but you mentioned, and I think, Mr. Kalant, you also mentioned, that driving after using marijuana decreased reaction time. Then you also said that its joint use with alcohol was where you saw increased numbers of motor vehicle accidents. Speaking of alcohol and marijuana usage, I assume that's recreational usage. But we don't know; it could possibly be somebody who is using marijuana for medical purposes and then mixing it with alcohol.

As we know, when people use pharmaceutical medications, it clearly says “do not consume alcohol while taking this medication”, yet people do, which increases the adverse effects of both the toxicity of the medication they might be taking with the pharmaceutical drug and the impairment caused by the alcohol in their system.

I know that alcohol is bad for you. We know there have been some longitudinal studies on the cardiovascular benefits of red wine usage and limited, controlled portions throughout your day. My question is, why are we allowing for this substance to be used or abused? It could be both. We know that alcoholism is a disease sometimes—not a disease; it’s considered a disorder I think now. I don't remember the actual term.

Professor Kalant, you had mentioned that when you're doing research, it's important to do a thorough cost-benefit analysis. You had mentioned that with the medical marijuana use, the costs as well as the benefits are being assessed and weighed when a doctor or a medical professional prescribes it as a treatment option. We're not looking at the benefits today in this study. We're only looking at the costs. I know it's difficult to do a thorough analysis here.

Could you speak about how is it that we can actually be doing a proper, thorough study when we're not?

10:10 a.m.

University of Toronto, As an Individual

Prof. Harold Kalant

It's surely not for me to comment on the task of the committee. I take no part in that.

10:10 a.m.

NDP

Rathika Sitsabaiesan NDP Scarborough—Rouge River, ON

Sure, maybe that was not fair on my part, then.

Because you have the experience and you said that since 1950-something—

10:15 a.m.

University of Toronto, As an Individual

Prof. Harold Kalant

It was since 1959.

10:15 a.m.

NDP

Rathika Sitsabaiesan NDP Scarborough—Rouge River, ON

—you've been doing research on alcohol and substance abuse.

Nevertheless, can you speak about alcohol for me, please, and about impairments in driving? Can you provide to the clerk of the committee comparative statistics on alcohol alone, and the usage of alcohol and impaired driving causing motor vehicle accidents—possibly even other adverse health effects of alcohol use and abuse—and compare that with cannabis use if you have those statistics? Or if you have any studies? If you have it today, please give it to us now. If you don't, could you give it to the clerk later?

10:15 a.m.

University of Toronto, As an Individual

Prof. Harold Kalant

I would be happy to give the clerk follow-up information. I can say that, in general, certainly alcohol is much more widely used than cannabis, and not surprisingly, it also causes serious health problems, more than cannabis, because of its wider use.

The question of why it's allowed is a different matter altogether.

10:15 a.m.

NDP

Rathika Sitsabaiesan NDP Scarborough—Rouge River, ON

Absolutely.

10:15 a.m.

University of Toronto, As an Individual

Prof. Harold Kalant

History, tradition, social beliefs and practices play a major role in what society does or does not tolerate.

10:15 a.m.

NDP

Rathika Sitsabaiesan NDP Scarborough—Rouge River, ON

Absolutely.

10:15 a.m.

University of Toronto, As an Individual

Prof. Harold Kalant

Alcohol has been used since before the beginning of human history. Attempts to stop its use have been carried out from time to time in various countries, and in some countries it is not used for religious reasons. However, attempts to prevent its use for non-medical reasons in our society have failed.

Almost every society has some psychoactive drug that is tolerated, that is incorporated into its traditions, its practices. Alcohol has been in our society for a long, long time. If we were starting from scratch, it's conceivable that we might have picked cannabis instead of alcohol, but we're not starting from scratch. When we talk about cannabis, we have to think about whether we are or are not adding cannabis to alcohol. That is a consideration that means that, necessarily, we are treating the two drugs somewhat differently.

Certainly you are right that alcohol also causes problems and is tolerated. Cannabis causes problems, and currently is not tolerated. It's illegal. When a drug is legal, the use tends to increase greatly because of easier availability. The price is usually cheaper when it is from legitimate sources than from illegitimate sources.

Those factors tend to increase use when it is legal. That is another consideration that has to be taken into account when doing cost-benefit balance. It's not just what the balance is now, but what the balance will be if we change practices in a way that influences the extent of use.

10:15 a.m.

Conservative

The Chair Conservative Ben Lobb

Thank you, Ms. Sitsabaiesan. Seven minutes comes pretty fast these days.

Next up is Mr. Lizon, for seven minutes.

Go ahead, sir.

May 1st, 2014 / 10:15 a.m.

Conservative

Wladyslaw Lizon Conservative Mississauga East—Cooksville, ON

Thank you very much.

Thank you, witnesses, for coming to the committee this morning.

I think the first question I have is probably for both doctors.

I've met with groups that advocate using medical marijuana, or marijuana, and some of them claim that smoking marijuana helps some groups of people much better than taking it orally, in the form of tablets.

Can you elaborate on this?

10:15 a.m.

University of Toronto, As an Individual

Prof. Harold Kalant

Dr. Kahan did touch on it, Mr. Chairman.

I will rely on you to direct questions to Dr. Kahan or to me, as you see fit.