As policymakers in Canada backtrack on decriminalization measures, a study published in the Journal of the American Medical Association (JAMA) finds that drug decriminalization in Oregon did not cause an increase in overdose mortality.
Though the increase in overdose deaths coincided with the adoption of Measure 110, the state’s Drug Addiction Treatment and Recovery Act, the authors of the study showed that the flood of fentanyl into Oregon’s unregulated drug market drove the increase in Oregon’s overdose deaths.
“A lot of people wrongly attribute the increase in overdose death rates that occurred in Oregon in recent years to Measure 110, but that’s not consistent with the evidence,” says Michael Zoorob, the study lead and a consultant at Rhode Island Hospital.
Oregon voters approved Measure 110 in 2020 decriminalizing the possession of small amounts of all banned drugs, and greatly boosting funding for treatment, harm reduction and other social supports. It took effect in February 2021 and was the first measure of its kind in the United States.
On March 1, 2024, following public and political backlash, Oregon legislators approved House Bill 4002, which recriminalized drug possession. That took effect on September 1, making low-level possession a misdemeanor punishable by up to 180 days in jail.
A statement from the Drug Policy Alliance called the move “a return to the failed approach of law and enforcement and the criminal legal system as the primary response to people struggling with substance use disorders, instead of health and service providers.”
The JAMA study demonstrated what Zoorob says may already seem “obvious” to many advocates: A shifting drug supply, principally the growing prevalence of fentanyl, drove the increase in Oregon’s overdose deaths in the relevant period.
In contrast, the authors concluded, “no association between M110 and fatal overdose rates was observed.”
“In a lot of studies, we do account for the arrival of fentanyl when we are speaking with participants in smaller-scale qualitative studies,” says Saba Rouhani, assistant professor of epidemiology at the NYU School of Global Public Health. “But we haven’t been systematically accounting for the fact that fentanyl hit these different states at different times.”
The research group used drug seizure data from the National Forensic Laboratory Information System to model the spread of fentanyl across the U.S.
“The first finding is the East to West pattern that people have talked about,” Zoorob says, noting that by the time fentanyl flooded the Oregon market, it had already ripped through 40 other states. “The change point in Oregon where we see fentanyl enter the market is roughly the same as when Measure 110 takes effect.”
Next, the researchers used a regression model to quantify how much of the changes in drug overdose death rates between states over time were attributable to fentanyl exposure. “We show that fentanyl exposure explains more than half of that variation, which is crazy,” notes Zoorob.
Zoorob’s team then replicated the findings of an earlier study that found decriminalization accounted for a 23 per cent increase in overdose deaths in the state. However, when they controlled for fentanyl, the effect of decriminalization was nullified.
“If you ignore the transition of the drug supply, we find a statistically significant effect with Measure 110 contributing to overdose,” Zoorob explains. “But what’s really happening here is that there’s this confounding variable: fentanyl exposure. If we adjust for that, the effect of Measure 110, or drug decriminalization, shrinks to zero.”
A recent Drug Policy Alliance report states that decriminalization in Oregon was designed to reduce the harms of drug criminalization, and that substantial progress was made under Measure 110. Advocates didn’t claim that decriminalization itself would make the drug supply much safer.
Under Measure 110, the state saw a reduction in drug possession-related arrests and pumped hundreds of millions of dollars into treatment. The report notes that decriminalization also saved Oregon nearly $40 million in criminal-legal system costs and caused a significant increase in the number of people accessing substance use disorder treatment and other services.
However, a state audit released January 2023 was critical of Measure 110, flagging a number of deficiencies in its implementation. One issue it highlighted was that the citizens’ panel overseeing new treatment funding was slow in delivering the money, and the health authority had not provided the panel with adequate support.
“The policy was actually a two-part policy,” says Rouhani of Measure 110’s decriminalization and funding elements. “The second part took longer to implement. The fact that the money and resources to really focus on improving health outcomes came later didn’t do the public impression of this policy any favors.”
Rouhani says we aren’t likely to see – nor be able to measure – the positive health outcomes from policy changes like decriminalization until they are in effect longer term.
“Given that these policies are now being repealed, it really limits our ability to see the impacts that decriminalization could have on fostering supportive trajectories of care for people who use drugs,” she says. “But we know that arresting people who use drugs is largely ineffective at deterring future use or crime and increases risks of a cascade of negative health outcomes.”
Criminalization and arrests are associated with a higher risk of overdose, create barriers to employment and housing, and disproportionately impact people of color and other marginalized populations. “We would expect that [removing criminalization] would in turn, translate to positive health outcomes longer-term,” Rouhani says.
Zoorob says it is beyond the scope of his paper to suggest whether other states should take up decriminalization. But he says he hopes it can help with the analysis of other drug policy decisions.
“I think we need to have some humility about how much we can learn from one intervention in a single state over a short period of time, or from a single study,” Zoorob notes. “But the key takeaway is that Measure 110 did not cause this increase in overdose deaths.
“We’re likely going to have this problem whenever we debate public policy. If it happens to coincide with changes in drug supply, people will potentially misattribute changes in public health outcomes to a certain policy, when really it comes down to broader macro issues.”
A version of this article was originally published by Filter, an online magazine covering drug use, drug policy and human rights through a harm reduction lens. Follow Filter on Facebook or X, or sign up for its newsletter.
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