Good morning, Mr. Chair, and members of the committee.
As indicated, my name is Michel Perron. I am the chief executive officer of the Canadian Centre on Substance Abuse, CCSA. I'm also joined by Dr. Amy Porath-Waller, senior research and policy analyst. Her primary research focus is on the health effects of cannabis.
To assist members with this important study on its harms, I'll be speaking about some issues related to cannabis, which could also interchangeably be referred to as marijuana. Specifically, I will touch on rates of use in Canada and awareness, health risks associated with use based on the latest research, and what we at CCSA can propose as a way forward.
In terms of rates of use, one in ten Canadians reported using cannabis in 2012, making it the most commonly used illicit substance. In terms of chronic use, we know that over a quarter of Canadians, youth and adults, who reported using cannabis in the past three months are daily users.
Canada's youth are the highest users of cannabis when compared to students in other developed countries. Although overall rates of use have been declining since 2008, youth still use cannabis at rates that are about 2.5 times higher than that of adults.
It's clear that young people use cannabis, but this vulnerable group mistakenly believes that it's a benign substance. When I use “vulnerable” here, I'm referring to their stage of brain development, as Dr. Smith just mentioned.
It should also be stated that cannabis is not a homogenous substance. It can, and does, have varying levels of THC, the psychoactive ingredient, and at levels quite different from what we've seen, even just recent years ago.
We also know that the earlier someone starts to use, the more likely they are to use more frequently, and increase their risk of dependence.
In order to get a better idea of what youth think about cannabis, CCSA conducted research with young Canadians across the country. I have copies of this report available for you today.
The results show that Canadian youth are very confused about cannabis. In the study, some said cannabis helps to improve their focus at school and that the drug can even prevent or cure cancer. Youth were also uncertain as to whether cannabis improves or impairs driving performance, and felt that smoking and driving was not as dangerous as drinking and driving. Moreover, youth often talked about how cannabis is natural, so they don't really think of it as a drug.
I'd like to now turn your attention to research that has been conducted on the health risks of cannabis use.
It's important to remember that some of this research is quite conclusive, as we heard from Dr. Smith just now. Other areas show mixed results, and in some areas the research is just very much beginning.
I'll organize my remarks around these three areas: the acute, or immediate, harms; short-term harms; and long-term harms.
In terms of acute harms, immediately upon using cannabis, research is clear that there are negative impacts on cognitive functioning. Specifically, it impairs concentration and decision-making, reaction time, memory, and executive functioning. All of these abilities are required to safely operate a vehicle or to pay attention in school, or go to work. There's also consistent evidence that cannabis use impacts the ability to drive safely and increases the risk of collision, and that this risk significantly increases when cannabis is combined with alcohol.
In terms of short-term harms, they can affect a person up to a month after using. Research consistently shows that cognitive deficits, which were referred to earlier, that are present during the acute phase can persist after that time. This means a negative impact on a person's ability to think, learn, and remember. Emerging research indicates that heavy chronic use may also lower a person's IQ.
In addition, there is consistent evidence that frequent use of cannabis is associated with an increased risk of experiencing mental health issues, such as psychotic episodes or schizophrenia. That risk increases when an individual has a family history of the disorder. Evidence is more mixed with respect to linkages between cannabis use, depression, and anxiety.
Marijuana can also be harmful to health and respiratory functions. Its smoke contains toxic substances similar to those in tobacco smoke, which means that inhaling this smoke can expose the lungs and airways to respiratory problems.
Cannabis smoke is also unfiltered, and users take larger, deeper puffs, thereby keeping the smoke in the lungs longer.
I should note, however, that the long-term effects of smoking cannabis on respiratory health, such as lung cancer, are less clear, and there is a need for additional research on this subject.
I know that the committee is also interested in the addictive properties of cannabis. Clinical research indicates that cannabis can lead to dependence. Studies have shown that cannabis triggers the brain's reward centre in both animals and humans. Clinical studies on heavy users, defined as weekly, also demonstrated withdrawal symptoms when use was discontinued, including around anxiety, physical tension, and disturbed sleep patterns.
According to recent data from the 2012 Canadian community health survey, over 5% of young Canadians age 15 to 24 met the criteria for cannabis abuse or dependence. This represents about a quarter of a million young Canadians. That is a significant number which I think we need to pause and consider as we go forward. For adults age 25 to 64, this number was less than 1%.
I will turn now to the effects on the developing brain.
To reinforce some of the messages we've heard, it's clear that as a society we should be concerned about whether and how much our young people are using cannabis. Adolescence is a time of rapid development that helps set the stage for later success in life. Conversely, it can also set the stage for experiencing challenges in adulthood. There is growing evidence that early and frequent use of cannabis can alter structural aspects of the developing brain, including those areas of the brain that are responsible for memory, decision-making, executive functioning, and motor coordination.
To repeat, those who use most often are at greater risk than adults. This can have significant consequences on a young person's life trajectory when their main role in life when they're young is to learn and grow.
Available data show that everything we can do to prevent, reduce or delay drug consumption will help reduce the harm to individuals and society, as well as reduce health care expenses.
In terms of a way forward, it's clear that cannabis is not a benign substance. The early or more frequent the use, the greater the potential for both acute and long-term harm. This points to the need for a comprehensive, multi-faceted approach to raise public awareness of the health effects of cannabis in order to reduce its use.
In this regard, through our health promotion and drug prevention strategy for Canada's youth, CCSA is working with partners to promote evidence-informed practices and advance knowledge about substance abuse prevention, including the prevention of cannabis use.
We have already done a great deal of work in this regard with the development of Canadian standards for substance abuse prevention for schools, families, and communities. We know that prevention works, but not just any kind of prevention. The standards help those who work in the field deliver quality services.
We're also working with a scientific advisory committee to clarify what we know and what we don't know about the effects of cannabis use on the developing brain. As well, we are looking at how to build resilience in youth in partnership with the sport and recreation communities.
Sound evidence-based prevention programs and awareness-building initiatives are key components of a continuum of services and support that include health promotion, early intervention, and treatment. I would caution the committee that these should not be taken in isolation. Substance abuse is a problem too complex to be addressed by any one approach or by any one group, and it's very much a concerted, collective approach around these areas that would make some true success and achieve a collective impact.
Mr. Chair, the topic of cannabis and its place in Canadian society will certainly occupy the public discourse for the near future. Perhaps that's an opportunity for us to correct some of the misunderstandings around the substance. It is, however, a complex issue with far-reaching implications on our collective health and safety, and it impacts our future when our young people are experimenting with a substance that affects their development. We've spent a lot of time trying to ensure that our youth are best equipped at school and in their jobs to be successful members of society in a knowledge-based economy to have a productive nation. This is clearly an issue that impacts that ability in the long-term way forward.
Like you, the CCSA is committed to reducing and preventing the harms associated with cannabis by carefully studying the evidence and by conducting additional research, as needed.
We welcome an ongoing dialogue similar to the discussion we're having today.
I would like to thank the committee for its interest in this issue of vital importance to the health of Canadians.
I would be happy to take any questions.
Thank you.