The Many Sides of the Cannabis Conversation

Illustration of cannabis plant

On October 17, 2018, Canada legalized cannabis for recreational use. In the medical, public health and health research community this was met with both cautious optimism and deep concern.

The complexity of legalization – from the age of use, to the adequate communication of health risks, to providing access to high-quality product – has sparked debate across the sector.

Four health experts share their views on the ongoing cannabis debate.

A public health approach to cannabis means getting the balance right

By Dr. Christopher Mackie, Medical Officer of Health, Middlesex-London Health Unit

The legalization of cannabis for nonmedical use ended almost 100 years of legal prohibition; yet we also know that cannabis carries some level of risk no matter how it is consumed and so it is important that legalization be accompanied by policy measures that limit this risk.

Using evidence-informed policy and practice, a public health approach to cannabis legalization addresses the health concerns of cannabis while aimingto reduce or eliminate the health and social harms resulting from its criminal prohibition. In simple  terms, social and health problems are lowest when we can avoid these two extremes – complete prohibition and free market commercialization.

This is known as the ‘paradox of prohibition.’ While cannabis as a substance carries health risks, criminal prohibition did not prevent use. Prior to legalization, nearly half of Canadians reported to have ever used cannabis and compared to their counterparts in other developed  countries, Canadian youth are the highest users of cannabis in the world.

Criminal prohibition carried tangible harms – criminal records and associated life-long consequences, including under employment, lack of educational attainment and stigma. Prohibition also created a thriving illegal market of unknown product quality, easily accessed by youth.

The potential for success lies in finding the right balance. There is a substantial body of evidence from years of research about alcohol and tobacco that shows overpromotion is linked to increased consumption, earlier initiation and increased harms.

Canada has a chance to get this balance right: protecting the health of the public by promoting lower-risk use for those who choose to use,  preventing and delaying use by youth, and providing an adequate supply of a safer, regulated product.

The regulatory framework for cannabis must adapt to emerging science

By Steven R. Laviolette, PhD, Professor, Anatomy & Cell Biology and Psychiatry, Schulich Medicine & Dentistry

Legalization of marijuana can be a positive step in the right direction provided that the regulatory framework from Health Canada is able to adequately adapt to emerging science and take into consideration the very  clear risks posed by adolescent cannabis exposure.

In my lab, we are examining how adolescent exposure to the main psychoactive compound in cannabis, Tetrahydrocannabinol (THC), can induce long-term vulnerability to certain mental health conditions. We use a rodent model of the adolescent brain development to model human teen use of cannabis and explore brain pathways known to be disturbed in serious psychiatric disorders like depression, anxiety, post-traumatic stress disorder, addiction and schizophrenia.

Results from our studies have demonstrated conclusively that the developing adolescent brain is exquisitely sensitive to the effects of THC and that even limited exposure can cause long-lasting brain alterations that  endure well into adulthood. Many of the molecular and neuronal adaptations identified by our team share astounding similarities to the neuropathology observed in schizophrenia, depression and anxiety disorders.

Since we know the human brain is experiencing important developmental processes all the way to age 25, there is a lot of concern regarding what age an individual can safely consume cannabis. Of course, this is a complex question because our research suggests that it really depends on the THC potency of the cannabis being used and the relative levels of cannabidiol (CBD), the other major phytochemical in cannabis. In fact, our research has shown that CBD can counteract many of the negative effects of THC on the brain and actually have therapeutic potential in treating disorders like anxiety, addiction and schizophrenia.

The challenges for developing a regulatory framework in Canada involve setting an appropriate age of access for young people, continuing to combat black market cannabis access and regulating the relative amounts of THC and CBD in strains of cannabis that are now commercially available.

Currently, legal ages of access to cannabis differ across provincial lines and only in the coming years will we be able to know conclusively if allowing access at 18 to 19 years of age, particularly to high-potency cannabis strains, may cause any dramatic shifts toward increased mental health problems among vulnerable populations.

“Canada has a chance to get this balance right: protecting the health of the public by promoting lower-risk  use for those who choose to use, preventing and delaying use by youth, and providing an adequate supply  of a safer, regulated product.” — Dr. Christopher Mackie

Cannabis legalization provides one more tool in aiding patients with chronic illness

By Dr. Michael Verbora, MD'13, Chief Medical Officer, Aleafia Health

The legalization of medical cannabis has provided a regulatory framework for patients to access high-quality  products to manage symptoms associated with various chronic illnesses.

Prior to legalized medical cannabis, patients were forced to grow cannabis or designate a grower and there was a lack of quality control. With a regulated framework, physicians can now authorize cannabis products and be aware of the CBD/THC content, and dose with milligram accuracy. This has led to a massive increase in patients seeking cannabis products and to date more than 350,000 Canadians are registered in the medical cannabis system with more than 18,000 physicians having written authorizations.

It has also led to a resurgence in cannabinoid research to help us better understand the risks and benefits of cannabinoid therapy. Having the option to trial medical cannabis for health presents physicians with one more tool in aiding patients. There are many patients who do well on medical cannabis and more evidence is emerging that it can lead to opioid or benzodiazepine reductions and improvements in quality of life.

Given the complexity of medical cannabis, it has also forced many patients to become educated on the cannabinoid product offerings and their health. Engaging patients with their health is important to optimize awareness and positive outcomes.

The legalization of recreational cannabis serves to reduce public health harms associated with unregulated cannabis products. There remains a majority of the market still accessing illicit products, but the government hopes that with time, consumers will switch to regulated legal access.

Unfortunately, there remains a product shortage of regulated legal cannabis and medical patients did suffer with poor access when legal access was turned on in October 2018. This access has improved, but specific product lines can be at times difficult to access, such as high CBD oils, due to limited products.

Glamourizing cannabis smoking will lead to chronic, life-shortening lung disease

By Grace Parraga, BSc'84, MSc'86, PhD, Professor, Medical Biophysics, Scientist, Robarts Research Institute

I’m not concerned about cannabis legalization, but I am deeply concerned about normalizing and glamourizing cannabis smoking and the fact that for some, legalization makes smoking seem more socially acceptable, sexy and safe.

It is obvious to me that after decades of experience working with the devastating effects of tobacco smoking including lung cancer, chronic obstructive pulmonary disease, emphysema and needless premature deaths, Canadians should be very concerned about the impact of cannabis smoking and second-hand cannabis smoke on early lung development in babies and children and on lung health and  resilience to infection in adults and seniors.

I know first-hand from the cannabis and tobacco smokers we study in the lab that the damage smoking causes starts early in the smallest airways and that patients cannot perceive or sense this until disease is very advanced, and too late to cure.

When we breathe in smoke, the burning or vapourized particles flow into the lung and deposit along its 1,500 kilometres of airways and 500-million air sacs. A neverending cycle of inflammation and tissue repair results in irreversible  lung destruction – the airways become abnormally thickened, blocked or completely obliterated and the air sacs are destroyed. We also know that women and Indigenous smokers are more prone to developing terminal lung disease.

I lose sleep at night concerned about the influence the cannabis industry has on Canadians’ decisions to smoke and I am deeply troubled that tobacco companies suppressed their own research about the damaging effects of smoking. These same companies are now considering purchasing cannabis companies, which opens up the potential for mixed cannabis and nicotine products, which will enhance addiction to smoking and expand sales and revenue.

The debilitating effects of smoking on lung health are undeniable, unnecessary and unconscionable. Researchers like me have a shared public responsibility to speak out and talk about our research, which shows that smoking causes chronic, life-shortening lung disease.