Highlights from a national study on substance-related acute toxicity deaths: Insights from coroners and medical examiners

Full article available: Thompson T, Rotondo J, Enns A, Leason J, Halverson J, Huyer D, Kuo M, Lapointe L, May-Hadford J, Orpana H. Exploring the contextual risk factors and characteristics of individuals who died from the acute toxic effects of opioids and other illegal substances: listening to the coroner and medical examiner voice. Health Promotion and Chronic Disease Prevention in Canada: Research, Policy and Practice. 2023 Feb;43(2):51. https://doi.org/10.24095/hpcdp.43.2.01



In recent years, substance-related acute toxicity deaths (sometimes referred to as 'overdose' or 'poisoning' deaths) have increased sharply and remain a significant cause of mortality in Canada. In response, local governments, provinces, and territories have implemented a variety of interventions and the Government of Canada has committed to a targeted public health response supported by a strong evidence base which includes the enhancement of relevant surveillance and research activities.

Coroners and medical examiners gain a unique perspective during the course of their investigations, which involve gathering information from a variety of sources to determine who died and how, when, where, and why the death occurred. A national qualitative study was conducted to draw on this information source and glean observations and insights from these experts by allowing them to use their own words to describe the context surrounding these deaths.

The study

Thirty-six semi-structured interviews were held with coroners, medical examiners, and toxicologists from eight provinces and territories across Canada (British Columbia, Saskatchewan, Manitoba, Ontario, Quebec, New Brunswick, Nova Scotia, and the Northwest Territories) between December 2017 and February 2018. Participants were asked to reflect upon the drug-related overdose deaths they had investigated between 2016 and 2017 to identify common characteristics among those who died, the substances involved, and potential missed opportunities for intervention or prevention. Interview transcripts were reviewed, coded, and grouped to identify key themes.

Key findings

  • People who died from substance-related acute toxicity came from all demographic and socioeconomic groups and had different histories of substance use. Histories of substance use included long-term, occasional, or first-time use, and chronic pain treatment.
  • Characteristics or contextual factors commonly observed among people who died included:
    • Using substances alone or in the presence of somebody who is unable to recognize the signs or respond in the event of an acute toxicity
    • Consuming substances of unexpected toxicity or composition (for example, substances contaminated with fentanyl)
    • Decreased substance tolerance as a result of not using while incarcerated or during a stay in a healthcare facility or residential treatment centre
    • Histories of mental illness, experiences of stigma, chronic pain, and lack of support or health care follow-up
  • People who died from a substance-related acute toxicity may have experienced more than one of these complex, interrelated contextual factors

Study limitations

Not all coroners and medical examiners were interviewed in each participating province and territory and not all provinces and territories in Canada participated in this study. Thus, the views presented here represent those of only a subset of the death investigation community. Recall bias may have affected responses, with answers reflecting more recent or memorable cases. Also, this study presents a snapshot of the characteristics of those who have died at the time when the interviews took place. As the situation continues to evolve, these characteristics may change.


We would like to thank all participants from the British Columbia, Saskatchewan, Manitoba, Ontario, Quebec, New Brunswick, Nova Scotia, and Northwest Territories Coroner and Medical Examiner Offices for taking the time to share their knowledge and thoughtful reflections on their experiences. We also thank all members of the Substance-related Overdose and Mortality Surveillance Task Group (formally the Opioid Overdose Surveillance Task Group) and the Forum of Chief Coroners and Chief Medical Examiners for their input and feedback.

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