More Restrictive Cannabis Policies Were Associated with Less Cannabis Use in Both Adults and Youth | Research

The takeaway

Analysis of U.S. state cannabis policies from 2002-2019 found that a 10-point increase in policy restrictiveness was associated with about a 1 percentage-point reduction in adult cannabis use and 0.2 points in youth use.

Cannabis policy researchers, state legislators, public health officials evaluating legalization impacts

10-point policy restrictiveness increase linked to ~1 percentage-point use reduction

What the researchers found

Using the Cannabis Policy Scale, a comprehensive measure of 17 state cannabis policy areas, more restrictive policies were significantly associated with lower past-month cannabis use. A 10 percentage-point increase in restrictiveness reduced adult use by 0.87-1.04 percentage points and youth use by 0.17-0.21 percentage points. The association held across multiple model specifications.

Why it matters

As states rapidly liberalize cannabis policies, this is among the most comprehensive analyses of how the full spectrum of cannabis regulations (not just legalization status) relates to use. The finding that policy restrictiveness matters for both adults and youth provides evidence for policymakers weighing liberalization against public health.

The numbers in context

10-point CPS increase (more restrictive) associated with: overall use reduction of 0.81-0.97 percentage points (ages 12+), adult reduction of 0.87-1.04 points (18+), youth reduction of 0.17-0.21 points (12-17). Data span 2002-2019. CPS measures 17 policy areas.

How the study worked

Repeated cross-sectional time series analysis using National Survey on Drug Use and Health state estimates from 2002-2019, linked to the Cannabis Policy Scale (CPS), which measures 17 policy areas weighted by efficacy and implementation. Three model specifications with state and year fixed/random effects.

What this study cannot tell us

Observational study cannot establish that policies caused the use changes. Cannot rule out reverse causation (states with lower use may adopt more restrictive policies). Self-reported cannabis use. CPS weights are expert-assigned and may not perfectly capture policy impact. Period ends in 2019, missing recent policy changes.

How to read the evidence

Strong evidence from a large, nationally representative time series spanning 17 years with multiple model specifications and a comprehensive policy measure.

When this study was published

2025 study analyzing U.S. state cannabis policies and use from 2002-2019.

The bigger picture

Most cannabis policy research focuses on binary legalization status, but the reality is that cannabis policy is multidimensional. This study shows that the overall restrictiveness of a state's cannabis policy environment, capturing everything from penalties to medical access to advertising rules, is consistently associated with use levels.

Questions still open

Which of the 17 policy areas have the strongest individual effects on use? Would extending the analysis to 2024 change the findings given accelerated legalization? Do restrictive policies reduce harmful use or just any use?

Common questions

Do cannabis laws actually affect how much people use?

Yes, this study found a consistent association: states with more restrictive overall cannabis policies had lower rates of cannabis use among both adults and youth. A 10-point increase in policy restrictiveness was linked to roughly a 1 percentage-point reduction in adult use.

Does legalization increase youth cannabis use?

This study found that more restrictive policies were associated with slightly lower youth use (0.17-0.21 percentage points per 10-point increase). However, the effect was smaller for youth than adults, and the study measured overall policy environment rather than legalization status alone.

Read the original research

The association between state cannabis policies and cannabis use among adults and youth, United States, 2002-2019.

Addiction (Abingdon, England), 120(1), 164-170

View on PubMed ↗Publisher’s paper ↗

Citation

Pessar, Seema Choksy; Smart, Rosanna; Naimi, Tim; Lira, Marlene; Blanchette, Jason; Boustead, Anne; Pacula, Rosalie Liccardo. (2025). The association between state cannabis policies and cannabis use among adults and youth, United States, 2002-2019.. Addiction (Abingdon, England), 120(1), 164-170. https://doi.org/10.1111/add.16663