Alcohol causes more harm overall in Canada than other drugs such as tobacco, opioids, cocaine, methamphetamine, and cannabis, according to an assessment by a panel of experts.

The study, published in the Journal of Psychopharmacology, used a multicriteria decision analysis (MCDA) to compare 16 of the most commonly used psychoactive substances in Canada. This method is designed to address complex issues by considering multiple types of harm.

“This is the first time in Canada that a group of researchers has attempted to look at harms other than purely pharmacological harms from substances,” said Holly Mathias, MA, PhD, assistant professor of family science at the University of Alberta in Edmonton. In addition, “this report looks at not only harm to the person who’s using the drug, which is what we would traditionally look at, but also harm to others.”

Alcohol Contributes to Major Harms

As part of the study, which was led by researchers at the Centre for Addiction and Mental Health, 20 experts in six Canadian provinces scored 16 drugs on a scale from 0 to 100 for each of 16 types of harm. Scores were weighted by the relative importance of each harm and combined to produce an overall harm score.

The types of harm include harms to people who use the drug (eg, death; damage to physical health; dependence; and loss of income, job, housing, or relationships) and harms to others (eg, injuries, impacts on children and family, environmental damage, and economic costs to the country).

The drugs that were rated most harmful, along with their overall harm score, included the following:

• Alcohol (79)
• Tobacco (45)
• Nonprescription opioids (33)
• Cocaine (19)
• Methamphetamine (19)
• Cannabis (15)

“It’s become unambiguous that alcohol contributes to major health and social harms at lower levels of use than were previously appreciated,” said Evan Wood, MD, PhD, professor of social medicine and addiction medicine physician at the University of British Columbia in Vancouver. He pointed to Canada’s Low-Risk Alcohol Drinking Guidelines, which were updated in 2023 to emphasize that harms start to accumulate at more than two standard drinks per week.

“We want to reduce the unhealthy use of alcohol, so that requires giving people factual information about the health risks,” said Wood. Especially since “alcohol is the drug of choice for many people in the United States and Canada.”

Geraint B. Osborne, PhD, professor of social sciences at the University of Alberta in Camrose, Alberta, said the findings resonate with his research involving cannabis users. “Many of my participants reported preferring cannabis to alcohol because they perceived [cannabis] as less harmful, less associated with aggression, easier to regulate in terms of consumption, and beneficial for managing stress and anxiety while promoting relaxation and creativity,” he said.

“Overall, the [new] study contributes to an ongoing, evidence-based reassessment of how societies understand and regulate substance-related harm,” he added. In particular, “prohibition — the war on drugs — has been a dismal failure, driven by ideology rather than evidence.”

The authors of the study pointed out several limitations of MCDA. For example, this assessment considers only the harms of the drug, not any potential benefits to the individual or society, such as medical use of the drug. The analysis also focuses on the general population aged 15 years and older, which misses harms to youth or specific subpopulations.

Understanding Harms Guides Policies

Mathias emphasized that the results represent harms at a population level, not the individual or family level, which are unique. “For example, if you’re a family member of a loved one who’s using opioids and you’ve seen the level of destruction that that’s had on their life and on your own life, the findings of this paper night not seem as relevant,” she said.

Nevertheless, this study offers policymakers data that they can use when deciding which health policies and programs to implement to support the most people. “Even though we know that there are lots of health-related harms to alcohol consumption,” said Mathias, “we haven’t done a great job as public health professionals or decision makers in implementing policies that might be more protective against alcohol-related harms.”

“When it comes to treatment [of unhealthy alcohol use], we need to move toward more evidence-based approaches,” Wood agreed. He pointed out that the new study doesn’t consider potential drug harms related to the use of alcohol alongside medications, such as those mentioned in the Canadian Clinical Guideline on High-Risk Drinking and Alcohol Use Disorder. “When it comes to commonly prescribed antidepressant medications like selective serotonin reuptake inhibitors [SSRIs], these have actually been proven in meta-analyses to provide no benefit in people with alcohol use disorder,” said Wood.

One 2015 study even found that people with alcohol abuse or dependence who took the SSRI citalopram had a greater number of heavy drinking days throughout the trial.

Unfortunately, “healthcare providers often don’t have conversations about alcohol with patients,” said Wood.

Wood was the co-chair of the Canadian Alcohol Use Disorder Guideline Committee. Mathias and Osborne reported having no relevant financial relationships.

Shawn Radcliffe is a freelance health and science journalist based in Ontario, Canada, with more than 15 years writing about general health, medical research, mental health, and other topics for print and online publications. Prior to this, he did laboratory and clinical research, and research administration at universities in Philadelphia and Portland, Oregon. He has a master’s degree in science education from Drexel University.