States with recreational cannabis laws saw a temporary 7.6% drop in opioid-related ER visits | Research

The takeaway

Recreational cannabis laws reduced opioid-related emergency department visit rates by about 7.6% for two quarters after implementation, with effects driven by men and adults aged 25-44, but the reduction faded after six months.

Drug policy researchers, public health officials, legislators evaluating cannabis legalization

7.6% reduction in opioid-related ED visits for 2 quarters after recreational cannabis legalization

What the researchers found

Event study models using ED data from 29 states (2011-2017) found recreational cannabis laws reduced opioid-related ED visit rates by approximately 7.6% for two quarters after implementation. Effects were concentrated among men and adults aged 25-44. The reduction dissipated after 6 months. Crucially, recreational cannabis laws did not increase opioid-related ED visits.

Why it matters

The opioid epidemic continues to worsen, and identifying policy tools that reduce opioid-related harms is urgent. While the effect was temporary, the finding that cannabis legalization did not increase opioid emergencies counters concerns about a gateway effect at the population level.

The numbers in context

29 states; 2011-2017 ED data; 7.6% reduction in opioid-related ED visits for 2 quarters post-implementation; effects driven by men and adults 25-44; effects dissipated after 6 months

How the study worked

Event study models using nearly comprehensive emergency department data from 29 US states from 2011 to 2017. Compared opioid-related ED visit rates before and after recreational cannabis law implementation, with pre-trend analysis to verify parallel trends.

What this study cannot tell us

Observational policy analysis cannot prove causation. Only 29 states with available ED data. Six-month dissipation of effects limits the practical significance. Cannot identify individual-level substitution behavior from population data.

How to read the evidence

Rigorous quasi-experimental design with large multi-state dataset, though observational nature and short-lived effects limit causal claims.

When this study was published

Published in 2021 using 2011-2017 data.

The bigger picture

The temporary nature of the reduction suggests that initial cannabis substitution behavior may not sustain over time, or that other factors (such as increasing fentanyl availability) may eventually overwhelm any protective effect of cannabis access.

Questions still open

Why did the protective effect fade after six months? Would the effect be sustained in states with more mature cannabis markets? Does the demographic specificity (men, ages 25-44) reflect who is most likely to substitute cannabis for opioids?

Common questions

Did recreational cannabis reduce the opioid crisis?

Temporarily. Opioid-related ED visits dropped about 7.6% in the first two quarters after implementation, but this effect faded after six months. The authors concluded cannabis legalization "may offer some help" but is "not a panacea."

Who benefited most?

The reduction was driven by men and adults aged 25-44, suggesting this demographic may be most likely to substitute cannabis for opioids when given legal access.

Read the original research

Recreational cannabis laws and opioid-related emergency department visit rates.

Health economics, 30(10), 2595-2605

View on PubMed ↗Publisher’s paper ↗

Citation

Drake, Coleman; Wen, Jiebing; Hinde, Jesse; Wen, Hefei. (2021). Recreational cannabis laws and opioid-related emergency department visit rates.. Health economics, 30(10), 2595-2605. https://doi.org/10.1002/hec.4377