BACKGROUND: In the US, 40 states and the District of Columbia (DC) have implemented medical cannabis legalization (MCL), while 24 states and DC have enacted some form of recreational cannabis legalization (RCL). We examined the association between cannabis legalization and law enforcement cannabis seizures to understand illegal drug market responses to increasing state cannabis legalization.
METHODS: Data on law enforcement cannabis seizures came from the High Intensity Drug Trafficking Areas (HIDTA) program. We tested the association between state-level RCL and MCL adoption and annual changes in cannabis seizures aggregated by state-year from 2010 to 2023 using a series of Poisson regression models that controlled for time-varying state demographic and law enforcement variables in addition to state and year fixed effects. To account for potential lag time between MCL/RCL effective dates and policy impacts on seizures, we conducted additional analyses with 1-year MCL/RCL lags.
RESULTS: Over the study period, there were 286,844 cannabis seizures by HIDTA-affiliated agencies, with 686 state-years of observation. In primary adjusted models, RCL adoption was associated with a significant decrease in cannabis seizures in MCL & RCL states versus MCL-only states, both immediately following RCL adoption (exp(ß)=0.55, 95% CI: 0.54, 0.56) and one year after RCL went into effect (exp(ß) for 1-year lag=0.62, 95% CI: 0.61, 0.64).
CONCLUSIONS: The adoption of RCLs in US states, beyond only MCLs, may help to reduce the size of illegal cannabis markets, or there may be shifting law enforcement seizure priorities in those states.
Cannabis legalization and law enforcement drug seizures: A state-level analysis of cannabis policy effects on cannabis seizures in the United States, 2010-2023
International Journal of Drug Policy [Epub 2026 Mar 10]. doi: 10.1016/j.drugpo.2026.105217.