“Working in the emergency department, I frequently treat patients for opioid overdose, only to see them return with another overdose on my next shift. Support from the PSI Foundation made it possible for me to study gaps in post-overdose treatment to reduce repeat overdose and death, while also allowing me to gain valuable research experience as a resident.” -Dr. Jessica Kent
About Dr. Jessica Kent
Dr. Jessica Kent is an emergency physician, medical toxicologist, clinical pharmacologist, and investigating coroner. She holds clinical appointments at St. Michael’s Hospital/Unity Health Toronto, the Ontario Poison Centre, the Hospital for Sick Children, the Office of the Chief Coroner for Ontario.
Dr. Kent is also an Assistant Professor and Clinician-Investigator in the Department of Medicine at the University of Toronto, with academic appointments in the Divisions of Emergency Medicine and Clinical Pharmacology & Toxicology.
Her research focuses on substance-related harms, opioid overdose, and emerging psychoactive substances, with a particular interest in forensic and medico-legal toxicology, including the interpretation of toxicology results in clinical care/overdose, and death investigation.
About the Funded Study
Being discharged from the emergency department after an opioid overdose represents a high-risk period for repeat overdose and death–making these situations vital to initiate Opioid Agonist Therapy (OAT). Medications such as buprenorphine, methadone, and slow-release oral morphine (SROM) have been proven to reduce mortality, but only when patients remain engaged in the treatment.
With her PSI Resident Research grant and funded study, titled “Trends in opioid agonist therapy retention after non-fatal opioid overdose,” Dr. Kent set out to examine whether increasing efforts to initiate OAT following an ED visit for opioid overdose have resulted in sustained treatment in Ontario–particularly in the context of an evolving illicit drug supply. As well, her study looked into treatment dose at time of discontinuation, and whether patients switched to another form of OAT after stopping therapy.
Thousands of Canadians die each year from opioid poisoning, many shortly after receiving emergency treatment for a non-fatal overdose. While medications for opioid use disorder significantly reduce the risks of repeat overdose and death, these benefits depend on patients staying in treatment long enough to receive them.
This PSI-funded, Ontario-wide study found that although the number of people started on OAT after overdose increased significantly over time, most patients unfortunately did not remain in treatment for long. Across the study period, the median duration of retention was just 17 days. Although its initiation increased by more than 1,000% over the 10-year study period, the treatment’s retention declined sharply.
Dr. Kent’s findings uncovered that OAT dose at time of discontinuation was low throughout the study period which may limit treatment effectiveness, particularly given today’s highly potent illicit opioid supply. Additionally, switching to another form of OAT after discontinuation was uncommon, suggesting that many patients were leaving treatment entirely rather than transitioning to another therapy.
As Ontario’s illicit opioid supply has become increasingly potent and unpredictable, the effectiveness of standard OAT approaches have been challenged. In 2026, the Toronto Drug Checking Service reported that only 2% of fentanyl purchased on the street contained fentanyl alone. Most samples also contained other substances, including potent nitazene opioids, veterinary sedatives and non-medical benzodiazepines.
Many Ontarians are not only dependent on opioids, but also on several other substances at the same time, making treatment more complicated. Some patients report that standard medications, such as buprenorphine, no longer feel strong enough to manage withdrawal symptoms, leading them to stop treatment early. Since OAT initiation can save lives—depending if treatment continues—this PSI-funded study is helping Dr. Kent and her team understand why people stop treatment, critical to improving overdose prevention and patient care.
Impact of the Funded Study
The study’s findings spotlight a major gap in care during one of the highest-risk periods for repeat overdose and death. While more patients are being started on treatment, extremely short treatment duration may limit their protective benefit. Improving retention in OAT represents a critical opportunity to prevent repeat overdoses, and ultimately to save lives in Ontario and beyond.
“Working in the emergency department, I frequently treat patients for opioid overdose, only to see them return with another overdose on my next shift,” says Dr. Kent. “Support from the PSI Foundation made it possible for me to study gaps in post-overdose treatment to reduce repeat overdose and death, while also allowing me to gain valuable research experience as a resident.”
Overall, this PSI-funded study provides the first population-level evidence that OAT retention following non-fatal opioid overdose is increasingly poor despite increases in treatment initiation. These findings raise important concerns about the effectiveness of current post-overdose treatment strategies, particularly standard dose buprenorphine initiation.
Dr. Kent’s teams’ findings were presented as a moderated poster at the American College of Medical Toxicology Annual Scientific Meeting in Boston, facilitating early dissemination and discussion among clinicians with expertise in treating this patient population. The project was also orally presented and won Top Faculty Research Presentation at the University of Toronto’s Tri-Divisions of Emergency Medicine Research Academic Day.
As an accepted moderated poster, this abstract was also published in the Journal of Medical Toxicology. Her team’s findings are hypothesis-generating and will inform future research focused on improving ED-based interventions following opioid overdose.
Knowledge translation-wise, the activities produced from this study include the presentation of the study abstract as a moderated poster at the American College of Medical Toxicology (ACMT) Annual Scientific Meeting, and publication of the abstract in the Journal of Medical Toxicology. Dr. Kent and her team are preparing a full manuscript for submission to a peer-reviewed journal, as well as a study infographic in partnership with ODPRN to be released in the near future. Following publication, they plan to disseminate the findings through targeted sharing on professional social media platforms.
Further to this, Dr. Kent’s next steps include research focused on optimizing post-overdose treatment strategies initiated in the ED to improve retention. This should include evaluation of OAT dosing strategies and other pharmacologic interventions to support sustained engagement in treatment, particularly in the context of an increasingly potent and heterogenous illicit drug supply.
This PSI-funded study provides evidence that patients initiated on OAT after ED treatment for non-fatal opioid overdose are not retained in therapy, irrespective of OAT initiated. Within the broader healthcare context within Ontario and beyond, these findings highlight treatment retention as a critical gap in overdose prevention efforts.

