Health Committee on May 1st, 2014

[Dr. Meldon Kahan]

Actually cannabis use is associated with an increased risk of death from suicide and from motor vehicle accidents, so it's not quite true that it has no associated mortality with it.

[Prof. Harold Kalant]

I want to make clear that what I said was that no deaths have been proven from overdose alone.

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

That's right, and that's what I was saying.

I wonder if either of you could continue on with regard to the explanation on youth and how cannabis affects the brain and short-term memory and cognitive issues as well.

Dr. Kahan.

[Dr. Meldon Kahan]

I think Dr. Kalant is far more of an expert on that, specifically on its effects on youth.

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

Thank you.

Dr. Kalant.

[Prof. Harold Kalant]

Thank you.

That did constitute a large part of the preliminary remarks that I read, and I would simply repeat that, acutely, there is temporary impairment of function, as there is with many drugs affecting the central nervous system. Alcohol, tranquilizers, and opiates all affect a variety of cognitive functions temporarily and reversibly.

However, what I'm concerned about is the effect on the developing brain, because the endocannabinoid system—that is the system that exists naturally in the nervous system and throughout the body, in which substances similar in actions to the plant cannabinoids are the actual transmitter substances that modify nerve function—during the in utero development of the fetus has been shown to increase the generation of nerve cells in their mobility to their final site but to impair their ability to establish connections with each other to set up the nerve circuits that are required for laying down memories, for learning skills, and for carrying out higher functions. That is the part that is at particular risk throughout the period of maturation of the brain, which continues at different rates up till the end of adolescence.

That's why I have stressed that people who begin use at a very early age—and there are, unfortunately, many who do—are exposing themselves to risks that are permanent in the sense that if they continue to use and inhibit the maturation process until the age when that would end anyway, then they can't recover what they have postponed. That's why concern about youth is particularly relevant when we are talking about cannabis.

[The Chair, Conservative, Ben Lobb]

Okay. Thank you very much.

Mr. Gravelle, you have five minutes.

[Claude Gravelle, NDP, Nickel Belt, ON]

Thank you, Mr. Chair.

Professor Kalant, one of the statements you made is that some prescribed drugs are more dangerous than cannabis is.

I don't know if you were in the room when I asked my first question about the lady who went from 17 drugs to two drugs. Can you tell us what percentage of drugs are more dangerous to the human body than cannabis is?

[Prof. Harold Kalant]

Unfortunately, that question isn't possible to answer without qualification, because when you say “dangerous”, are you talking about acute danger? Are you talking about fatality? Are you talking about serious impairment of function in the immediate period of action of the drug, or are you talking about long-term health problems? The answer is different for different drugs, according to which type of danger you are talking about.

[Claude Gravelle, NDP, Nickel Belt, ON]

Let's talk about the long term.

[Prof. Harold Kalant]

In the long term, I would say that alcohol and cannabis are probably quite similar.

[Claude Gravelle, NDP, Nickel Belt, ON]

I was talking about prescribed drugs.

[Prof. Harold Kalant]

Oh, prescribed drugs.... Well, obviously opiates are dangerous both acutely and in the long term, acutely because it is possible to cause death by an overdose by suppressing respiration, and chronically, because addiction is well known with opioids and has important effects not only upon health but upon social function and social integration. However, cannabis also is capable of causing addiction and therefore can cause similar problems, though if you ask me if there is a difference in severity, I would say that probably the edge is greater for opioids.

If you're talking about tranquilizers or benzodiazepines and anti-anxiety drugs or hypnotic sedatives, again, deaths from overdose are possible. The effects on function—on coordination, judgment, the ability to drive a car safely and so on—are similar among benzodiazepines, alcohol, barbiturates, and cannabinoids. I think it's not a very profitable exercise to try to grade them in degree of risk. They all have risks, but in general for medical use the dosages are controlled in an effort to achieve the greatest benefit with the least risk, and the instructions that a doctor gives to a patient generally say, do not use more than so many times a day, do not use for more than two weeks, and so on.

With cannabis, there are no instructions given. For medical use, there are or should be, but we don't have enough experience yet to know how effective that advice is to patients. But for non-medical use, there are no instructions. Therefore, I would have to say that the risk overall in the long term is probably greater, because there are no effective controls for non-medical use.

[Claude Gravelle, NDP, Nickel Belt, ON]

Thank you.

We've heard today that cannabis causes impairment when driving, for example. Do you think that taking 17 prescribed drugs in a day would cause impairment also?

[Prof. Harold Kalant]

Well, it depends on what drugs you're talking about, of course. If you're talking about cardiovascular drugs, renal drugs, or gastrointestinal drugs, I'm not sure you can demonstrate that they would have much effect on function. But if you're talking about nervous system drugs, yes, and one of the risks is certainly, in contemporary medicine, the risk of overdose; that is, of combined use of large numbers of drugs without adequate thought as to what the combined effects may be.

[Claude Gravelle, NDP, Nickel Belt, ON]

Thank you.

Dr. Kahan, I think in your testimony you suggested or said that cannabis causes mood changes. Would you be prepared to say that prescription drugs also cause mood changes?

[Dr. Meldon Kahan]

Yes, of course they can. I think, though, the question is, what the therapeutic benefit of prescribing cannabis is versus its risks. If cannabis is prescribed, the risks of opiates and benzodiazepines are not going to go down. It's not an either-or thing. Opiates and benzodiazepines have terrible problems, but there is far greater evidence of effectiveness, so I don't think that smoked marijuana is a legitimate medicine except in extremely specialized circumstances, such as patients with severe neuropathic pain.

[The Chair, Conservative, Ben Lobb]

Okay. Thank you, Mr. Gravelle.

[Claude Gravelle, NDP, Nickel Belt, ON]

Thank you, Chair.

[The Chair, Conservative, Ben Lobb]

We have one minute allocated to Mr. Young, and then that will be it.

[Terence Young, Conservative, Oakville, ON]

Then we're done. Thank you, Chair.

Thank you, Dr. Kahan. I want to thank you so much for helping to dispel this myth that the regulatory system of alcohol is a wonderful success and that if we just decriminalize marijuana, tax it, and regulate it, everything will be fine. I looked at a recent CAMH study that says 54.9% of students in Ontario between grades 7 and 12 drink alcohol illegally on occasion, so we know that regulation is a failure.

When I served on the Alcohol and Gaming Commission of Ontario, I did 300 hearings for liquor licences. At that time in Ontario, back in 2003, $500-million worth of illegal alcohol was sold in Ontario in booze cans and after-hours clubs, so the idea that if we decriminalize or legalize marijuana, that's going to solve the problem and everybody's going to stop buying illegal marijuana is preposterous. I want to thank you very much for putting that on the record.

[The Chair, Conservative, Ben Lobb]

Okay. Thank you.

Briefly, please, and then we have to wrap up.

[Prof. Harold Kalant]

I'll be very brief.

I would agree completely. Also, I would point out that the hope that legalizing would eliminate the black market would be true only if it were sold legally at a lower price than the black market. If you do that, the use is likely to increase greatly. As long as the price is high to control use, then the black market will not be eliminated.

[The Chair, Conservative, Ben Lobb]

Thank you very much.

I thank our guests for taking the time to be here.

Certainly, to our members, the second hour was much smoother than the first hour, so thank you.

The meeting is adjourned.