Cannabis Legalization and Youth Cannabis Use: Evidence on the Importance of Enforcing Retailer Compliance

• In Event: What Happens After Legalization?: The Role of Cannabis Policy in Markets, Policing, Youth, and Patient Health

Abstract

Background: As of 2025, twenty-four states and the District of Columbia have legalized adult-use cannabis, and forty states permit medical use. Cannabis legalization has been shown to increase adult cannabis use in the U.S. but results on youth use are mixed. This study investigates one potential source for the mixed findings: inconsistent enforcement of the minimum legal purchase age (MLPA).  States vary in their use of random compliance checks of retailers with escalating penalties for noncompliance. This variation parallels enforcement of minimum purchase ages for alcohol and tobacco, where evidence suggests that compliance checks can reduce underage sales, though effects depend on enforcement design and frequency. 

Methods: We combine survey responses on self-reported cannabis use among 8th, 10th and 12th grade youth in Washington state (N= 178,649) with administrative data on retailer inspections and compliance checks from Washington State Liquor and Cannabis Control Board over the period 2010-2023.  We examine impacts of local compliance checks applying difference-in-differences methods that are robust to a staggered policy rollout with dynamic and heterogeneous treatment effects on various measures of cannabis use, perceptions of risk and harms, and source of cannabis.  

Results:  We find that the introduction of compliance checks within a city leads to a 7.56% reduction in the probability of past-month cannabis use among youth. We document limited evidence that simple inspections are associated with any change in behavior. We observe some heterogeneity across youth, with stronger effects for boys than girls, those closer in age to the MLSA than younger youth, and youth who are White.  

Conclusions:  The lack of previous attention given in the literature to heterogeneous enforcement of MLPA may have contributed to a downward bias in the estimated impact of legalization on youth consumption in the U.S. These findings suggest that states can mitigate youth access to cannabis through active enforcement of purchase age restrictions, and that evaluations of cannabis legalization's effects on adolescents should account for the regulatory enforcement environment in which legalization operates.

Author

• Rosalie Liccardo Pacula, University of Southern California
  Presenting Author