It has been one year since Canada legalized recreational cannabis on October 17, 2018. At the time, little was known about cannabis, since its classification as a controlled substance made conducting research difficult. In the last year, researchers have been busy playing catch up, and there is still much more to learn.

Below is just a small selection of the many cannabis research topics being investigated by St. Joe’s researchers:

1. How do we decide how much to charge for cannabis?

Researchers were curious about the pricing of legal versus illegal cannabis. How much are people willing to pay for legal cannabis before they seek a cheaper, illegal alternative?

It’s believed that legal cannabis is safer than illegal sources, since quality is strictly controlled and the product should be free of contaminants. As well, many who were against legalization were placated by the tax revenue it would generate – assuming people bought it legally.

A unique St. Joe’s study found that people treated legal cannabis as a superior commodity, and they were willing to pay slightly more for it compared to illegal cannabis. This was an important finding, as governments needed to set prices low enough to prevent the illegal market from expanding, yet high enough to cover the production cost.

2. Can cannabis help with sleep?

Cannabis has long been reported by users to have some association with sedation and sleep, though little research has been done on the topic. In a systematic review, researchers at St. Joe’s and McMaster evaluated current research on the effects of cannabinoids on sleep.

One of the problems they found is that current research tended to focus on the use of cannabis for the treatment of chronic health conditions, such as multiple sclerosis or PTSD – sleep was rarely the primary focus. Combined with other limiting factors, such as small sample sizes and examining sleep in the context of another illness, the existing research was not sufficient. New research projects, dedicated to studying sleep as the primary outcome and with large sample sizes, are still needed.

3. What about chronic pain and PTSD?

Though Veterans are a small segment of the Canadian population, they are disproportionally affected by medical conditions like chronic pain and post-traumatic stress disorder (PTSD) as a result of their service.

A 2018 editorial by St. Joe’s researchers noted that the evidence for positive therapeutic effects of cannabis for most medical conditions is lacking, but there is moderate quality evidence for pain relief. The editorial explained that much more research among Veteran populations is needed. Interestingly, at the population-level, medicinal cannabis legalization was associated with reductions in opioid, antidepressant, and anti-anxiety prescriptions.

The researchers also cautioned against the potential risks of cannabis use – motor impairment that increases the risk of car accidents, chronic use that may lead to cannabis use disorder, cognitive deficits, increased risk of psychotic disorders, and bronchitis.

4. How does smoking cannabis compare to smoking tobacco and cigarettes?

There is a long academic history that shows how tobacco smoke is associated with increased respiratory tract infections (amongst a host of other health concerns, including cancer). Previous research has firmly established that tobacco smoke can lower the antiviral processes of the lungs. But what about cannabis smoke?

Researchers at St. Joe’s have started comparing tobacco and cannabis smoke, in order to see if there are similar effects on the immune system of the lungs. Due to the past restrictions on using cannabis in the lab, there is a knowledge gap when it comes to cannabis safety. The Firestone Institute for Respiratory Health, with funding from the Ontario Lung Association, is now conducting research on combusted (smoked) cannabis.

5. I hear a lot about cannabidiol (CBD), a non-psychoactive component of cannabis. What potential applications might it have?

One area where CBD may prove useful is in the treatment of alcohol use disorder, commonly known as alcoholism. Researchers at St. Joe’s, McMaster, and Homewood Research Institute confirmed some interesting effects of CBD in mice and cell cultures.

They found that CBD has a protective effect on the hippocampus – an area of the brain that has a role on behaviour, memory, and emotion – against adverse effects of alcohol. It was also found to reduce liver toxicity and steatosis (fattening of the liver) from alcohol use. CBD even lowered cue-based and stress-based urges for alcohol in mice.

CBD appears to have promise as a medicinal therapy for alcoholism, though further research and rigorous clinical trials are still needed. It remains to be seen whether the positive effects of CBD observed in mice and cell cultures will translate to humans.

The Bottom Line

Since cannabis has only been legal for one year, there is very little research on the subject. It is also a plant with many varying aspects – chemical content varies by strain (THC, CBD, and other cannabinoids), consumption methods differ (smoked, vapourized, ingested), and artificial methods to increase THC concentration may amplify the more harmful effects. As well, since public policy is always changing (medicinal, then recreational legalization; introduction of storefronts; the sale of edibles), research has to adapt to these trends.

St. Joseph’s Healthcare Hamilton, in partnership with McMaster University, is home to several centres that conduct cannabis research. This includes the Michael G. DeGroote Centre for Medicinal Cannabis Research, the Peter Boris Centre for Addictions Research, and the Firestone Institute for Respiratory Health.

For more information, the Centre for Medicinal Cannabis Research maintains a portal of research publications, summaries, and knowledge syntheses, curated by cannabis research experts.