One-Year Association of Drug Possession Law Change With Fatal Drug Overdose in Oregon and Washington.

Importance: Two states modified laws to remove or substantially reduce criminal penalties for any drug possession. The hypothesis was that removing criminal penalties for drug possession may reduce fatal drug overdoses due to reduced incarceration and increased calls for help at the scene of an overdose.
Objective: To evaluate whether decriminalization of drug possession in Oregon and Washington was associated with changes in either direction in fatal drug overdose rates.
Design, Setting, and Participants: This cohort study used a synthetic control method approach to examine whether there were changes in drug possession laws and fatal drug overdose rates in Oregon and Washington in the postpolicy period (February 1, 2021, to March 31, 2022, in Oregon and March 1, 2021, to March 31, 2022, in Washington). A counterfactual comparison group (synthetic controls) was created for Oregon and Washington, using 48 states and the District of Columbia, that did not implement similar policies during the study period (January 1, 2018, to March 31, 2022). For 2018-2021, final multiple cause-of-death data from the National Vital Statistics System (NVSS) were used. For 2022, provisional NVSS data were used. Drug overdose deaths were identified using International Statistical Classification of Diseases and Related Health Problems, 10th Revision underlying cause-of-death codes X40-X44, X60-X64, X85, and Y10-Y14.
Exposures: In Oregon, Measure 110 went into effect on February 1, 2021. In Washington, the Washington Supreme Court decision in State v Blake occurred on February 25, 2021.
Main Outcome: Monthly fatal drug overdose rates.
Results: Following the implementation of Measure 110, absolute monthly rate differences between Oregon and its synthetic control were not statistically significant (probability = 0.26). The average rate difference post Measure 110 was 0.268 fatal drug overdoses per 100 000 state population. Following the implementation of the policy change in Washington, the absolute monthly rate differences between Washington and synthetic Washington were not statistically significant (probability = 0.06). The average rate difference post Blake was 0.112 fatal drug overdoses per 100 000 state population.
Conclusions and Relevance: This study found no evidence of an association between legal changes that removed or substantially reduced criminal penalties for drug possession in Oregon and Washington and fatal drug overdose rates. Additional research could examine potential other outcomes as well as longer-term associations with fatal drug overdose overall and across racial and ethnic groups.