Increasing recreational cannabis access at the county level in Colorado was associated with fewer opioid prescription fills and inpatient visits but not with reductions in total morphine equivalents or emergency department visits.
Health policy researchers, opioid crisis analysts, cannabis policy makers
Fewer opioid fills but no reduction in total morphine equivalents
What the researchers found
Using county-level variation in recreational dispensary allowances across Colorado, recreational cannabis exposure was associated with significantly fewer 30-day opioid fills (coefficient: -117.6, P<0.01) and inpatient visits (coefficient: -0.8, P=0.03), but not with reductions in total morphine milligram equivalents or ED visits. Counties without prior medical cannabis access experienced greater reductions.
Why it matters
By exploiting natural variation in dispensary access at the county level, this study provides more granular evidence than typical state-level analyses, revealing that the cannabis-opioid substitution effect may have limits.
The numbers in context
2,048 county-quarter observations; 2013-2018 prescribing data; 2011-2018 inpatient data; 30-day fills decreased significantly (P<0.01); inpatient visits decreased (P=0.03); total MME and ED visits not significant
How the study worked
Observational quasi-experimental study using county-level Colorado data (2011-2018) with a differences-in-differences framework. Combined Prescription Drug Monitoring Program data, Colorado Department of Revenue licensing data, and Colorado Hospital Association records across 2,048 county-quarter observations.
What this study cannot tell us
Colorado-specific findings may not generalize to other states. County-level analysis may miss within-county variation. Cannot determine whether individuals actually used cannabis instead of opioids. Time period may not capture longer-term effects.
How to read the evidence
Well-designed quasi-experimental study exploiting natural policy variation, though single-state analysis and ecological design limit generalizability.
When this study was published
Published 2023 using 2011-2018 data
The bigger picture
The mixed results suggest that cannabis access may reduce some opioid metrics (number of prescriptions, hospitalizations) without necessarily reducing overall opioid consumption, complicating the narrative that cannabis simply substitutes for opioids.
Questions still open
- Why did prescription counts decrease without a corresponding decrease in total morphine equivalents? Are remaining prescriptions at higher doses?
Common questions
Did recreational cannabis reduce opioid use in Colorado?
Did prior medical cannabis access matter?
Read the original research
Impact of Recreational Cannabis Legalization on Opioid Prescribing and Opioid-Related Hospital Visits in Colorado: an Observational Study.
Journal of general internal medicine, 38(12), 2726-2733
Citation
Buttorff, Christine; Wang, George Sam; Wilks, Asa; Tung, Gregory; Kress, Amii; Schwam, Dan; Pacula, Rosalie Liccardo. (2023). Impact of Recreational Cannabis Legalization on Opioid Prescribing and Opioid-Related Hospital Visits in Colorado: an Observational Study.. Journal of general internal medicine, 38(12), 2726-2733. https://doi.org/10.1007/s11606-023-08195-3