Health Committee on May 6th, 2014

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

But they reported smoking it.

[Dr. Andra Smith]

But it could have been a year before. It could have been within six months. It could have been once.

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

Yes I know. That's the point that I wanted to raise. Is there some scientific study?

I know there are a lot of studies being made of heavy users, but what about those people not smoking more than, I don't know, six joints in the whole year?

[Dr. Andra Smith]

Right. I think that the recent study that was done by Dr. Breiter, which Dr. Sabet was talking about, was on casual use among university students. They were finding significant differences.

[Dr. Kevin Sabet]

We're looking at what outcome we are concerned with. Obviously if we're looking at major structural changes in the brain, we wouldn't expect to see that with one in four times use, sir. Then when we're looking at driving, if you've only used once in the past year and you're intoxicated that one time and you get behind the wheel of a car, that's clearly going to have a negative outcome. It just depends on what outcome you're looking for.

We would not have expected Dr. Smith's research to show somebody who had smoked a year or six months ago to show those changes in the brain, because she was looking at people who had it in their urine; current users were those people explored. Clearly we wouldn't have seen among heroin users structural changes in the brain if they had used one to four times in the last year.

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

I don't disagree with you, but at the same time, if we want to compare people smoking marijuana and driving, we could say the same thing about alcohol use.

[Dr. Kevin Sabet]

Of course you could.

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

We're talking about scientific data. That's all I'm interested in. I know that you bring those examples but we must play fair with all the different substances.

[The Chair, Conservative, Ben Lobb]

Mr. Morin, there's no time for another question; you're over time.

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

Okay, thank you.

[The Chair, Conservative, Ben Lobb]

Mr. Wilks, for five minutes.

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

Thank you to the witnesses for being here today.

I will carry on with the topic that my colleague, Mr. Morin, was speaking to with regard to the uses.

In my previous life as a police officer and qualified as an expert with regard to marijuana through the Supreme Court of British Columbia, I'm curious about a couple of things.

I do school talks all the time. I did one last week in my riding. With regard to the use by kids, kids come up with some pretty interesting answers to why they would use marijuana, but they can't come up with any answers as to why they shouldn't use it because of all the myths that come with it: marijuana cures cancer, or if they smoke it once, it's okay because their mom says it's okay.

There are a couple of things that I want to ask Dr. Smith with regard to the frontal lobe of the brain and how marijuana attacks that frontal portion. Are brain cells destroyed? If they are, do they recover, or is there a potential that some of them never recover?

[Dr. Andra Smith]

There are cannabinoid receptors all through the brain, the prefrontal cortex, the hippocampus, the cerebellum. The cannabis affects the neurotransmitter modulation.

Do they actually destroy neurons? In animal models, they have been shown to. I think what Dr. Sabet was saying about recovery in that New Zealand study, it seems that we don't know exactly. That would suggest that they don't.

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

If I could interject, would you agree with regard to what Mr. Morin was saying, that from a scientific perspective, we haven't been investigating marijuana long enough to determine its long-term effects? Truthfully, we've ignored it. We've looked at alcohol for hundreds of years. We've looked at cigarettes for a long time. From the perspective of marijuana, we've done a very poor job of education and it's become this benign type of drug.

Would you agree that we just have not studied it long enough to be able to determine its long-term effects?

[Dr. Andra Smith]

I think we do have a number of longitudinal studies that suggest there are negative long-term effects. Is there more evidence that has to be gained? Of course. But we do have quite a bit of scientific evidence to suggest that there is long-term impact.

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

Thank you.

Dr. Sabet, you talked about vaporizing with regard to e-cigarettes or m-cigarettes. As you're aware, in Canada there is absolutely no regulation with regard to e-cigarettes or any of that type of cigarette, and in fact, with vaporizing you can get a higher potency of THC that can be ingested into your system.

Can you talk a little about that from the perspective of vapour as opposed to what we see as just ingesting from a normal marijuana cigarette?

[Dr. Kevin Sabet]

A lot of kids, unfortunately, as you mentioned, have many misunderstandings about this. They think that if you don't smoke it and you just eat it or vaporize it, it will be safer. We know from studies on vaporization of various things that it is very difficult to control the heat level, which would mean that you are heating up....

Remember, when marijuana is combusted, when it's heated up, you are not consuming 500 components, but 2,000 components, most of which are unknown in terms of the effect on you. So it is definitely a risk and a gamble.

I think a lot of people think that vaporization is safer. In reality, it seems to be a way to disguise marijuana use, especially at school and with parents and others. We know that the THC concentrates can be much higher, and therefore more dangerous.

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

With regard to the levels of THC—

[The Chair, Conservative, Ben Lobb]

Mr. Wilks, you're out of time.

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

Thank you.

[The Chair, Conservative, Ben Lobb]

Next up is Mr. Morin.

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

Thank you, Mr. Chair.

I'm reading right now the discussion part of the study, and I would like Dr. Smith to comment on it. It says as follows:

This study examined BOLD fMRI response among regular current marijuana users and nonusers during a Go/No-Go task. Although differences in behavioral performance were non-significant, the two groups differed in their pattern of neural activation....

Can you comment on the reasons that the differences in behaviour performance were non-significant?

[Dr. Andra Smith]

When we design fMRI tasks, typically we want both groups to be able to perform the tasks so that we're actually looking at activity in the brain related to the type of processing we're interested in. We design the tasks so that they're not necessarily simple, but doable. We want the performance to be similar. That's the strength of fMRI, that they can do the task, they're successful at doing the task, with the same reaction time and the same errors, but their brains are doing something different. They're having to compensate. They're having to use more brain resources to perform the tasks.

This is the challenge, that when you get out into the real world and the tasks are more difficult, that compensation might not be good enough, essentially.

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

Thank you very much.

Later on it says, on page 131, that nicotine use must be considered to affect results even after accounting for it statistically, because a percentage of kids smoke nicotine. Can you comment on the situation and why it must be considered to affect results even after accounting for it statistically?

[Dr. Andra Smith]

We had to take into account nicotine use and alcohol use because they do impact the brain. We were able to control for a number of substances, a number of variables, in our analysis. We have seen that nicotine use does impact the brain, particularly in high doses.

We're just making the statement that you have to consider all drugs. They interact when they're used at the same time, in the same person. It all has to be taken into account, because it's not a benign drug either.