OBJECTIVES To develop a more robust understanding of the relationship between increased recreational marijuana access and opioid overdose deaths. Increasing opioid-related deaths in conjunction with the rising popularity of liberalized marijuana laws make additional research examining the interrelation of both a timely and insightful question.

STUDY DESIGN We use synthetic control method to assess the impact of opening recreational marijuana dispensaries via recreational marijuana legalization (RML) on opioid death rates in Colorado, Washington, and Oregon. These states were the first to introduce recreational marijuana legalization, providing a sufficiently long post-treatment period to draw fruitful policy-related insights.

METHODS We utilize state-level data collected from the Centers for Disease Control, Bureau of Labor Statistics, US Census Bureau, American Foundation for AIDS Research's Opioid and Health Indicators Database, and other data sources to construct our synthetics.

RESULTS Our analysis shows each synthetic control's average treatment effect is approximately -6.49 for Colorado, -2.89 for Washington, and -4.8 for Oregon. However, these findings were not statistically significant. Additional robustness checks performed on each synthetic yield a consistent negative relationship but non-significance.

CONCLUSIONS We did not find significant relationships between recreational marijuana dispensary openings and opioid death rates.