In recent months, several media outlets have investigated an Oregon law that decriminalized possession of small amounts of controlled substances, including heroin, cocaine, and methamphetamine, for some persons. The articles have included information suggesting that the law may be responsible for continued increases in overdose deaths. Today, new research led by NYU Grossman School of Medicine published online in JAMA Psychiatry suggests that in Oregon and Washington, two states that implemented drug decriminalization policies in early 2021, there is no evidence of an association between decriminalization and fatal drug overdose rates.

The findings are the result of a collaboration between the Center for Opioid Epidemiology and Policy at NYU Langone, the Network for Public Health Law, and the Centers for Disease Control and Prevention (CDC). The research team’s goal was to investigate whether fully or partially decriminalizing drug possession changed rates of overdose deaths in either state in the first year after the policy change.

Decriminalization advocates assert that laws like those passed in Oregon and Washington will result in increased calls for help by people experiencing or witnessing an overdose and reduce incarceration, which itself is associated with fatal overdose. Critics, meanwhile, argue that decriminalizing the possession of small amounts of drugs might increase drug use and subsequent fatal overdose. This research found no evidence to support either outcome in the first year after the policy change.

“Our analysis suggests that state decriminalization policies do not lead to increases in overdose deaths,” said Corey Davis, JD, MSPH, adjunct assistant professor in the Department of Population Health at NYU Grossman School of Medicine, a member of the Center for Opioid Epidemiology and Policy, and the study’s senior investigator.

Another study published by Davis and colleagues last month found that the Oregon and Washington decriminalization policies dramatically reduced arrests for drug possession and did not lead to increased arrests for violent crimes. “These two studies show that drug decriminalization measures in Oregon and Washington reduced arrests and did not increase overdose deaths. Taken together, these findings signal reduced harm to people who use drugs and possibly their communities as well,” said Davis.

Policymakers and public health experts are increasingly looking to decriminalization and other harm reduction measures to stem the tide of opioid overdose deaths in the United States, driven largely by fentanyl, a synthetic opioid up to 50 times more potent than heroin and involved in approximately two-thirds of all U.S. overdoses. More than 100,000 people continue to die from drug overdoses each year.

How the Study Was Conducted

The team of investigators examined one year of post-decriminalization data in Oregon (February 2021 through March 2022) and Washington (March 2021 through March 2022) using death certificate data from the CDC’s National Vital Statistics System. Oregon’s decriminalization measure is commonly referred to as “Measure 110” while Washington’s change was prompted by a state Supreme Court decision that ruled the state’s drug possession law was unconstitutional.

The researchers then constructed a synthetic control group made up of 13 states that had similar rates of overdose to Oregon and 18 states that had similar rates of overdose to Washington pre-decriminalization. After the investigators found no statistical significance in overdose death rates between Oregon, Washington, and the control group, the investigators conducted a sensitivity analysis incorporating an additional seven months of provisional data. The findings did not change.

“This study is an important first look at the impact of drug decriminalization on overdose, but continued monitoring is needed. In addition to reducing penalties for drug possession, Measure 110 in Oregon directed hundreds of millions of dollars of cannabis revenue to increasing access to programming aimed at reducing overdose risk. However, these funds were not distributed until after our study period,” said Spruha Joshi, assistant professor in the Department of Epidemiology at the University of Michigan School of Public Health and co-lead author of the study. “It will be important to continue to monitor overdose rates as more data become available to assess the impact of the distribution of these funds.”

In addition to Davis and Dr. Joshi, other study collaborators include co-lead author Bianca D. Rivera, MPH, and Magdalena Cerdá, DrPH, MPH, from the Center for Opioid Epidemiology and Policy; Gery P. Guy Jr., PhD, MPH, and Andrea Strahan, PhD, MPP, from the CDC; and Haven Wheelock, MPH, of Outside In, Portland, Oregon. Davis is also with the Network for Public Health Law, a nonpartisan nonprofit organization.

Funding for the study was provided by the CDC. The findings and conclusions are those of the authors and do not necessarily represent the official position of the CDC.

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Sasha Walek
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