More Cannabis Stores in Washington Counties Linked to Fewer Opioid and Accidental Poisoning Deaths | Research

The takeaway

Washington state counties with more cannabis stores per capita had significantly lower rates of accidental poisoning and opioid deaths, with no increase in motor vehicle, suicide, or homicide mortality.

Legalization policymakers, opioid crisis researchers, public health officials

17% lower opioid mortality with higher cannabis store density

What the researchers found

Cannabis store density was negatively associated with accidental poisoning deaths (IRR 0.83, 95% CI 0.73-0.93) and opioid mortality (IRR 0.83, 95% CI 0.70-0.99). No significant associations were found for motor vehicle accidents, homicide, or suicide deaths across 39 Washington counties from 2009-2020.

Why it matters

One of the central concerns about cannabis legalization is whether increased access leads to more injury and death. This county-level analysis from an early-legalizing state suggests the opposite for poisoning deaths, with no detectable harm across other mortality categories.

The numbers in context

39 counties; 2009-2020; 12,933 suicide deaths; 6,761 motor vehicle deaths; 8,858 opioid deaths; store density IRR for opioid mortality 0.83; IRR for accidental poisoning 0.83; stores grew from 31 to 447.

How the study worked

Fixed-effect Poisson regression using county-level mortality data from individual death records and cannabis license/sales data across 39 Washington counties for 2009-2020. Cannabis retail stores grew from 31 in 2014 to 447 in 2020.

What this study cannot tell us

Ecological (county-level) design cannot establish individual-level substitution behavior. Confounders like naloxone distribution, treatment access, and prescription monitoring programs evolved during the same period. Correlation does not imply cannabis stores caused reduced mortality.

How to read the evidence

Well-designed ecological study with 12 years of county-level data, but ecological design limits causal inference.

When this study was published

2025 publication with 2009-2020 data

The bigger picture

The association between cannabis availability and reduced opioid mortality aligns with a growing body of research suggesting some people substitute cannabis for opioids. The accidental poisoning finding is newer and warrants further investigation.

Questions still open

Is the reduced opioid mortality driven by cannabis-opioid substitution or other factors correlated with store presence?
Do other early-legalizing states show the same county-level mortality patterns?

Common questions

Do more cannabis stores mean more deaths?

No. In Washington state, counties with more cannabis stores per capita actually had lower rates of accidental poisoning and opioid deaths. No increase was found in motor vehicle, suicide, or homicide mortality.

Does cannabis legalization reduce opioid deaths?

This Washington state analysis found cannabis store density was associated with 17% lower opioid mortality at the county level. However, this ecological association does not prove causation, as other factors changed simultaneously.

Read the original research

Cannabis retail store density and county-level mortality from injury in the state of Washington from 2009-2020.

The American journal of drug and alcohol abuse, 51(1), 107-115

View on PubMed ↗Publisher’s paper ↗

Citation

Kerr, William C; Ye, Yu. (2025). Cannabis retail store density and county-level mortality from injury in the state of Washington from 2009-2020.. The American journal of drug and alcohol abuse, 51(1), 107-115. https://doi.org/10.1080/00952990.2024.2436524