Drug harms in Canada: A multi-criteria decision analysis

A new Canada-wide scientific assessment has found that alcohol causes more harm overall than any other drug in the country—ranking far above tobacco, opioids, cocaine, methamphetamine and cannabis.

Led by multiple CRISM researchers and Node Principal Investigators (NPIs), in collaboration with national and international experts, this study was published in the Journal of Psychopharmacology, on January 27, 2026. Using a multi-criteria decision analysis (MCDA), the study aimed to compare 16 of the most harmful and commonly used psychoactive substances in Canada across 16 types of harm. These included short- and long-term physical, mental and social harms to people who use drugs (e.g. loss of life, damage to physical health), and harms to others (e.g. environmental damage, economic costs), among other factors.

Primary Author

Jean-François Crépault, PhD

Jean-François (JF) is Senior Policy Advisor at the Centre for Addiction and Mental Health, where he develops and communicates evidence-informed public policy in the area of substance use to government and other stakeholders. His research focus is public health approaches to substance use and, more broadly, the governance of addictive substances and behaviours.

National and International Experts

Matthew Bonn (Changemark Research+Evaluation, Vancouver, BC, Canada)
Michael Chaiton (Centre for Addiction and Mental Health, Toronto, ON, Canada, Institute of Medical Science, University of Toronto, ON, Canada)
Karleigh Darnay (Centre for Addiction and Mental Health, Toronto, ON, Canada)
Bernard Le Foll (Centre for Addiction and Mental Health, Toronto, ON, Canada, Department of Psychiatry, University of Toronto, ON, Canada)
Sean Patenaude (Centre for Addiction and Mental Health, Toronto, ON, Canada)
Peter Selby (Centre for Addiction and Mental Health, Toronto, ON, Canada
Institute of Medical Science, University of Toronto, ON, Canada
Adam Sherk (Canadian Institute for Substance Use Research, University of Victoria, Victoria, BC, Canada, Canadian Centre on Substance Use and Addiction, Ottawa, ON, Canada)
Kevin D. Shield (Centre for Addiction and Mental Health, Toronto, ON, Canada, Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada)
Maria Zhang (Centre for Addiction and Mental Health, Toronto, ON, Canada, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, Canada)
Rose Crossin (Department of Population Health, University of Otago, Christchurch, New Zealand)
Lawrence Phillips (Drug Science, London, United Kingdom)
David Nutt (Drug Science, London, United Kingdom
Division of Psychiatry, Imperial College, London, United Kingdom)

CRISM Researchers

Cayley Russell

Research Manager - Ontario Node

Jürgen Rehm

Principal Investigator - Ontario Node

David C. Hodgins

Principal Investigator - Prairies Node

Elaine Hyshka

Nominated Principal Investigator - Prairies Node

Didier Jutras-Aswad

Nominated Principal Investigator - Quebec Node

Eugenia Socías

Principal Investigator - BC Node

Sherry Stewart

Nominated Principal Investigator - Atlantic Node

Mark Asbridge

Co-Principal Investigator - Atlantic Node

Farihah Ali

Nominated Principal Investigator - Ontario Node

Robert Henry

Nominated Principal Investigator - Paspinam

Multi-criteria decision analysis (MCDA) has been used to quantify drug harms in the United Kingdom, the European Union, Australia, and New Zealand. This study presents the result of an MCDA conducted in Canada, with the aim of informing Canadian drug policy and contributing to public understanding of drugs’ relative harms.

MCDA tackles complex questions where no single measure captures the full picture. Rather than focusing on a single outcome, such as deaths or addiction, this approach brings together multiple forms of harm, from health effects to social and community impacts, and weights their relative importance.

A panel composed of 20 experts from six provinces determined 16 drugs to evaluate on 16 dimensions of harm took part in a two-day decision conference. The panel first scored each drug on a scale from 0 to 100 for each of the 16 types of harm, then weighted the relative importance of each type of harm. Theses scores were then combined to produce an overall harm score for each substance, showing which drugs cause the greatest total harm in Canada.

The analysis found that alcohol had the highest overall harm score, at 79 out of 100, followed by:

Tobacco (45)
Non-prescription opioids (33)
Cocaine (19)
Methamphetamine (19)
Cannabis (15)

These scores represent population-level harm, not how dangerous a drug might be for any one person. They reflect both how risky a substance is and how widely people use it, capturing its overall impact on people and society. The finding that alcohol causes the most harm aligns with results from previous MCDA studies in the United Kingdom, the European Union, Australia and New Zealand.

The findings point to a clear need for drug policy that is informed by the real scale of harm in Canada. For alcohol in particular, the researchers point to proven, evidence-based measures such as controlling price, limiting availability, and restricting marketing and promotion as effective ways to reduce harm. More broadly, they emphasize that policymakers should reflect on the harms caused by substances as well as those caused by the laws and regulations that govern them.

Harm Criteria and Definitions

Harm to people who use the drug

Drug-specific mortality

Extent to which the use of the drug causes death from acute toxicity or overdose.

Drug-related mortality

Extent to which life is shortened by the use of the drug, excluding drug-specific mortality.

Drug-specific damage to physical health

Extent to which the use of the drug damages physical health directly.

Drug-related damage to physical health

Extent to which the use of the drug damages physical health indirectly.

Dependence

Extent to which a drug creates a propensity or urge to continue use despite adverse consequences.

Withdrawal

Extent to which a drug causes withdrawal symptoms upon cessation and the severity of those symptoms.

Short-term impairment of mental functioning

Extent to which a drug impairs mental functioning in the short term.

Long-term impairment of mental functioning

Extent to which a drug impairs mental functioning in the longer term.

Loss of tangibles

Extent of loss of tangible assets such as income, housing, educational opportunities or employment.

Loss of relationships

Extent of loss of relationships or connections with family and friends.

Harm to others

Injury

Extent to which the use of a drug contributes to injuries to others, directly or indirectly.

Organized criminal activity

Extent to which the use of a drug involves or contributes to organized criminal activity.

Family and social adversity

Extent to which the use of a drug negatively affects family and social well-being.

Environmental damage

Extent to which the production or use of a drug causes environmental harm.

International damage

Extent to which the use of a drug contributes to harms at an international level.

Economic cost

Extent to which the use of a drug generates direct and indirect societal costs.

Total Harms

Harm to users and to others

Substance	Harm to Users	Harm to Others	Total
Alcool	52.415	26.375	78.790
Tabac	27.413	17.299	44.712
Opioids (NP)	19.546	13.904	33.450
Cocaine	5.147	13.833	18.980
Methamphetamine	7.972	10.908	18.880
Cannabis	8.021	6.931	14.952
Crack	5.749	3.941	9.690
Opioids (P)	5.980	2.430	8.410
ENDs	4.005	2.739	6.744
Benzodiazepines	1.819	0.796	2.615
MDMA	1.148	0.777	1.925
Solvents	1.340	0.564	1.904
Mushrooms	0.884	0.444	1.328
Ketamine	0.958	0.369	1.327
Stimulants	0.620	0.398	1.018
LSD	0.644	0.369	1.013

For more information, please contact Dr Jean-François Crépault at JeanFrancois.Crepault@camh.ca

Crépault J-F, Russell C, Asbridge M, et al. Drug harms in Canada: A multi-criteria decision analysis. Journal of Psychopharmacology. 2026;40(2):286-295.

Access the press release from CAMH here.

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