HRI is the proud recipient of $100,000 in funding from the Canadian Centre on Substance Use and Addiction (CCSA) and Health Canada to study the effects of cannabis legalization on at-risk populations, including people requiring treatment for mental illness and substance use disorder (SUD).
Following a 2020 call for proposals to explore cannabis policy and research, CCSA awarded funding for 19 projects. Topics range from cannabis legalization and mental health to a comparison of legal versus illicit cannabis sales.
HRI’s Director of Evaluation, Dr. Jean Costello, will lead the HRI study, in collaboration with researchers at the Peter Boris Centre for Addictions Research in Hamilton, Ontario. The team will examine the potential effects of cannabis legalization among sub-populations who already tend to use cannabis at elevated rates, including:
- People receiving treatment for SUD, and
- People receiving treatment for concurrent disorders (i.e., people living with SUD as well as another psychiatric condition)
Researchers say that any significant change in cannabis use in these clinical populations may have implications for available treatment programs and services.
“To date, only a handful of empirical studies have examined the effects of legalizing recreational cannabis, and most of these have focused on youth and the general adult population,” says Dr. Costello.
“None of the studies have involved people in treatment settings living with substance use disorder or concurrent disorders.”
She notes that findings could provide a unique and meaningful contribution to the body of evidence that healthcare providers and policy makers can use when designing future treatment approaches.
An approach that leverages existing partnerships
Thanks to longstanding partnerships that HRI holds with Homewood Health Centre and St. Joseph’s Healthcare Hamilton, Dr. Costello’s team will have access to patient data that straddles the cannabis-legalization timeline.
“We’re using data that has been collected as part of standard clinical practice at both treatment facilities,” says Dr. Costello.
Specifically, researchers will examine changes over the course of cannabis legalization in two clinical samples of patients from the Addiction Medicine Program at Homewood Health Centre and the Concurrent Disorders Programs at St. Joseph’s Healthcare Hamilton.
In total, the data extracted from both programs includes more than 2,800 unique patients.
“The richness of the available data will enable us to examine pre- and post-legalization changes as a natural experiment within two clinical programs,” says Dr. Costello.
Closing knowledge gaps
Findings from this study will provide an early snapshot of the potential impact of cannabis legalization on people living with substance use disorder and concurrent disorders in clinical settings – an area previously unexplored by researchers.
The available data will also enable researchers to explore relationships between cannabis use, other substance use, and psychiatric symptoms, such as depression, anxiety, and symptoms of trauma.
“With any significant policy change – such as the legalization of cannabis – there comes an urgent need to understand its effects on the health and well-being of Canadians,” says Dr. Costello.
“Thanks to CCSA, we have an opportunity to shed light on the potential impacts of this policy among specific at-risk populations. The findings from this study will be shared widely so that policies and treatment approaches can be adapted where needed to best serve people across Canada.”
Members of the project team include:
- Jean Costello, PhD (Co-Principal Investigator)
Director of Evaluation, HRI
- James MacKillop, PhD (Co-Principal Investigator)
HRI Senior Scientist
Director, Peter Boris Centre for Addiction Research
Director, Michael G. DeGroote Centre for Medicinal Cannabis Research
- Sarah Sousa, MSc (Co-Investigator)
Senior Research Associate, HRI
- Alysha Cooper, MSc (Co-Investigator)
Data Analyst, HRI
- Jennifer Brasch, MD, FRCPC (Research Partner/Knowledge User)
Psychiatrist, St. Joseph’s Healthcare Hamilton
- Yelena Chorny, MD (Research Partner/Knowledge User)
Chief of Addiction Medicine, Homewood Health Centre