Exploring Unregulated Substance Use Health Data in Ontario, Canada: Identifying Gaps, Addressing Challenges, and Uncovering Opportunities

Farihah Ali^1,2,3*Justine Law^1,2Cayley Russell^1,2Sameer Imtiaz^1,2Ahmed Bayoumi^4,5,6,7,8,9Dan Werb^10,4,7,8Jürgen Rehm^{1,11,12,13,14,2}

• ¹Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, Toronto, Canada
• ²Canadian Research Initiative in Substance Matters, Ontario Node, Toronto, Canada
• ³Division of Social and Behavioural Health Sciences, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
• ⁴Centre on Drug Policy Evaluation, MAP Centre for Urban Health Solutions, St. Michael's Hospital, Toronto, Canada
• ⁵Institute for Clinical Evaluative Sciences, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
• ⁶Department of Medicine, University of Toronto, Toronto, Canada
• ⁷Institute of Health Policy Management and Evaluation, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
• ⁸Division of General Internal Medicine, St. Michael's Hospital, Toronto, Canada
• ⁹Institute of Medical Science, Temerty Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
• ¹⁰Division of Infectious Diseases and Global Public Health, School of Medicine, University of California, San Diego, La Jolla, California, United States
• ¹¹Department of Psychiatry, Dallas Lana School of Public Health, University of Toronto, Toronto, Canada
• ¹²Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
• ¹³Institut Für Klinische Psychologie Und Psychotherapie, Technische Universität Dresden, Dresden, Germany
• ¹⁴Center for Interdisciplinary Addiction Research, University of Hamburg, Hamburg, Hamburg, Germany

Canada's overdose epidemic underscores the urgent need for high-quality, comprehensive, and timely national health data to inform evidence-based policies, population health management, and targeted intervention strategies. Using the province of Ontario, Canada, as a case study, this paper examines the current landscape of unregulated substance use health data, including both administrative and non-administrative health data sources. Health data on unregulated substance use in Ontario are fragmented, inconsistently collected, and poorly shared across organizations and jurisdictions. This creates significant barriers for researchers and decision makers in accessing timely and reliable information. Moreover, significant gaps persist in key areas, including prevalence estimates, treatment uptake, drug use profiles, marginalized populations, and disaggregated sociodemographic data. These deficiencies reflect and compound limitations at the national level, and hinder comprehensive analyses and informed decision-making, as well as progress towards coordinated national surveillance. To address these challenges, we propose several key recommendations: 1) standardize and integrate data to enhance consistency and interoperability among data sources; 2) improve data availability and accuracy to strengthen reporting mechanisms, increase transparency, and enable real-time monitoring of substance use trends, and 3) reduce barriers to data collection, analysis, and dissemination through enhanced collaboration and innovation. These strategies will improve provincial response efforts and contribute to building a national surveillance system that supports evidence-based decision-making to more effectively address the overdose crisis.