Drugs being decriminalized in Oregon and Washington has not led to any increase in overdose deaths, new research has found.

In the years after the possession of small amounts of controlled substances, including heroin, cocaine and methamphetamine, was decriminalized in Oregon and Washington in early 2021, there has been no evidence of an association between decriminalization and fatal drug overdose rates, a new study in the journal JAMA Psychiatry reveals.

"Our analysis suggests that state decriminalization policies do not lead to increases in overdose deaths," study author Corey Davis, an assistant clinical professor with the Center for Opioid Epidemiology and Policy in the Department of Population Health at NYU Grossman School of Medicine, said in a statement.

The NYU Grossman School of Medicine researchers analyzed one year of overdose death data in Oregon, from February 2021 to March 2022, and in Washington, from March 2021 through March 2022. They then compared these states to 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 in Washington pre-decriminalization. They found that there was no statistical significance in overdose death rates between the states and the control group.

Newsweek reached out to the study authors for comment.

opioid drugs
Stock image of two heroin syringes surrounded by scattered prescription opioids. Research has found that the decriminalization of drugs in Oregon and Washington has not led to an increase in overdose deaths.

Caroline S Copeland, associate professor of pharmacology and toxicology at King's College London and director of the National Programme on Substance Abuse Deaths, told Newsweek: "Majority acute drug toxicity/overdose is either by cardiorespiratory depression (slowed/stopped heart rate and breathing) by sedative drugs (e.g., heroin, fentanyl, diazepam) or heart attack by stimulants (e.g., cocaine). A small proportion is due to health conditions as a result of drug use (e.g., infection) and trauma due to actions undertaken while intoxicated (e.g., road traffic collision)."

The opioid class, which includes heroin, morphine and fentanyl, is most associated with drug-related overdoses. In 2021, 98,268 people died from drug overdoses in the United States alone.

The data shows that while drug overdose rates were not observed to increase, they did not decrease either.

"[This] shows that criminalizing possession of drugs that can cause fatality appeared to have little impact on whether somebody possessed and used these drugs or not: those that did so while possession was criminalized continued to post-decriminalization, but also that decriminalization did not appear to encourage further people to possess and use drugs that can cause fatality," Copeland said.

"I've emphasized the phrase 'drugs that can cause fatality' as not all drugs are usually considered able to cause death—cannabis is a great example of this. A recent study conducted in my group over a 20-year period and near 3,500 deaths in England where cannabis was detected had a single death attributed solely to cannabis use.

"As this JAMA Psychiatry study does not appear to have examined non-fatal drug use there could be a huge amount of increased non-fatal drug use that has been captured by this study," she said.

The study suggests that people who use drugs with risk of fatality were not deterred from using them when possession was criminalized, but equally that people were not encouraged to initiate use of these drugs when their possession was decriminalized.

Stock image of fentanyl. In 2021, 98,268 people died from drug overdoses in the United States.

"It is important to recognize that there are many harms associated with non-fatal drug use," Copeland said. "For example, the devastating effect of chronic xylazine use which can cause skin ulcers to form, which if becoming infected can lead to limb amputation. Another would be death due to driving whilst under the influence of drugs—are deaths of other drivers or pedestrians considered drug-related if killed by an intoxicated driver?

"Is it to do with less contamination from other drugs/less shame about seeking medical help? There are many factors at play—for example, there could have been more use of drugs that can cause fatality, but increased incidence of seeking help may have saved more lives," Copeland said.

The study authors hope to investigate the impacts of decriminalization of drugs in more detail, including drugs like cannabis. Washington has since re-criminalized possession of drugs.

"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," 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, said in a statement.

"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," she said.

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