By Alexandra Keeler

A study links B.C.’s safer supply and decriminalization to more opioid hospitalizations, but experts note its limitations

A new study says B.C.’s safer supply and decriminalization policies may have failed to reduce overdoses. Furthermore, the very policies designed to help drug users may have actually increased hospitalizations.

“Neither the safer opioid supply policy nor the decriminalization of drug possession appeared to mitigate the opioid crisis, and both were associated with an increase in opioid overdose hospitalizations,” the study says.

The study has sparked debate, with some pointing to it as proof that B.C.’s drug policies failed. Others have questioned the study’s methodology and conclusions.

“The question we want to know the answer to [but cannot] is how many opioid hospitalizations would have occurred had the policy not have been implemented,” said Michael Wallace, a biostatistician and associate professor at the University of Waterloo.

“We can never come up with truly definitive conclusions in cases such as this, no matter what data we have, short of being able to magically duplicate B.C.”

Jumping to conclusions

B.C.’s controversial safer supply policies provide drug users with prescription opioids as an alternative to toxic street drugs. Its decriminalization policy permitted drug users to possess otherwise illegal substances for personal use.

The peer-reviewed study was led by health economist Hai Nguyen and conducted by researchers from Memorial University in Newfoundland, the University of Manitoba and Weill Cornell Medicine, a medical school in New York City. It was published in the medical journal JAMA Health Forum on March 21.

The researchers used a statistical method to create a “synthetic” comparison group, since there is no ideal control group. The researchers then compared B.C. to other provinces to assess the impact of certain drug policies.

Examining data from 2016 to 2023, the study links B.C.’s safer supply policies to a 33 per cent rise in opioid hospitalizations.

The study says the province’s decriminalization policies further drove up hospitalizations by 58 per cent.

“Neither the safer supply policy nor the subsequent decriminalization of drug possession appeared to alleviate the opioid crisis,” the study concludes. “Instead, both were associated with an increase in opioid overdose hospitalizations.”

The B.C. government rolled back decriminalization in April 2024 in response to widespread concerns over public drug use. This February, the province also officially acknowledged that diversion of safer supply drugs does occur.

The study did not conclusively determine whether the increase in hospital visits was due to diverted safer supply opioids, the toxic illicit supply, or other factors.

“There was insufficient evidence to conclusively attribute an increase in opioid overdose deaths to these policy changes,” the study says.

Nguyen’s team had published an earlier, 2024 study in JAMA Internal Medicine that also linked safer supply to increased hospitalizations. However, it failed to control for key confounders such as employment rates and naloxone access. Their 2025 study better accounts for these variables using the synthetic comparison group method.

The study’s authors did not respond to Canadian Affairs’ requests for comment.

Correlation vs. causation

Chris Perlman, a health data and addiction expert at the University of Waterloo, says more studies are needed.

He believes the findings are weak, as they show correlation but not causation.

“The study provides a small signal that the rates of hospitalization have changed, but I wouldn’t conclude that it can be solely attributed to the safer supply and decrim[inalization] policy decisions,” said Perlman.

He also noted the rise in hospitalizations doesn’t necessarily mean more overdoses. Rather, more people may be reaching hospitals in time for treatment.

“Given that the [overdose] rate may have gone down, I wonder if we’re simply seeing an effect where more persons survive an overdose and actually receive treatment in hospital where they would have died in the pre-policy time period,” he said.

The Nguyen study acknowledges this possibility.

“The observed increase in opioid hospitalizations, without a corresponding increase in opioid deaths, may reflect greater willingness to seek medical assistance because decriminalization could reduce the stigma associated with drug use,” it says.

“However, it is also possible that reduced stigma and removal of criminal penalties facilitated the diversion of safer opioids, contributing to increased hospitalizations.”

Karen Urbanoski, an associate professor in the Public Health and Social Policy department at the University of Victoria, is more critical.

“The [study’s] findings do not warrant the conclusion that these policies are causally associated with increased hospitalization or overdose,” said Urbanoski, who also holds the Canada Research Chair in Substance Use, Addictions and Health Services.

Her team published a study in November 2023 that measured safer supply’s impact on mortality and acute care visits. It found safer supply opioids did reduce overdose deaths.

Critics, however, raised concerns that her study misrepresented its underlying data and showed no statistically significant reduction in deaths after accounting for confounding factors.

The Nguyen study differs from Urbanoski’s. While Urbanoski’s team focused on individual-level outcomes, the Nguyen study analyzed broader, population-level effects, including diversion.

Wallace, the biostatistician, agrees more individual-level data could strengthen analysis, but does not believe it undermines the study’s conclusions. Wallace thinks the researchers did their best with the available data they had.

“We do not have a ‘copy’ of B.C. where the policies weren’t implemented to compare with,” said Wallace.

B.C.’s overdose rate of 775 per 100,000 is well above the national average of 533.

Elenore Sturko, a Conservative MLA for Surrey-Cloverdale, has been a vocal critic of B.C.’s decriminalization and safer supply policies.

“If the government doesn’t want to believe this study, well then I invite them to do a similar study,” she told reporters on March 27.

“Show us the evidence that they have failed to show us since 2020,” she added, referring to the year B.C. implemented safer supply.

This article was produced through the Breaking Needles Fellowship Program, which provided a grant to Canadian Affairs, a digital media outlet, to fund journalism exploring addiction and crime in Canada. Articles produced through the Fellowship are co-published by Break The Needle and Canadian Affairs.

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