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

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.

Kerr, William C et al.·The American journal of drug and alcohol abuse·2025·ModerateEcological Study
RTHC-06813Ecological StudyModerate2025RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Ecological Study
Evidence
Moderate
Sample
Not reported

What This Study 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.

Key Numbers

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 They Did This

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.

Why This Research 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 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.

What This Study Doesn't 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.

Questions This Raises

  • ?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?

Trust & Context

Key Stat:
17% lower opioid mortality with higher cannabis store density
Evidence Grade:
Well-designed ecological study with 12 years of county-level data, but ecological design limits causal inference.
Study Age:
2025 publication with 2009-2020 data
Original Title:
Cannabis retail store density and county-level mortality from injury in the state of Washington from 2009-2020.
Published In:
The American journal of drug and alcohol abuse, 51(1), 107-115 (2025)
Authors:
Kerr, William C(6), Ye, Yu(2)
Database ID:
RTHC-06813

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-Control
Cross-Sectional / ObservationalSnapshot without intervening
This study
Case Report / Animal Study
What do these levels mean? →

Frequently Asked 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 More on RethinkTHC

Cite This Study

RTHC-06813·https://rethinkthc.com/research/RTHC-06813

APA

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

MLA

Kerr, William C, et al. "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, 2025. https://doi.org/10.1080/00952990.2024.2436524

RethinkTHC

RethinkTHC Research Database. "Cannabis retail store density and county-level mortality fro..." RTHC-06813. Retrieved from https://rethinkthc.com/research/kerr-2025-cannabis-retail-store-density

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.