Cannabis Legalization Increased Cannabis Use But Did Not Affect Tobacco Use or Co-Use | Research

The takeaway

In a national US cohort tracked from 2017-2021, cannabis use rose 3.3% while tobacco declined 1.9%, with both medical and recreational legalization increasing cannabis use but having no spillover effect on tobacco or co-use.

Policy makers, public health officials, and researchers studying legalization's broader substance use impact.

Cannabis legalization had no spillover effect on tobacco use or co-use

What the researchers found

Cannabis use increased 3.3% from 2017-2021 while tobacco/nicotine use declined 1.9%. Both medical and recreational legalization were associated with increased cannabis use, with recreational legalization having 1.13 times larger effect. Neither type of legalization was associated with changes in tobacco/nicotine use or co-use of cannabis and tobacco.

Why it matters

A major concern about cannabis legalization has been potential spillover effects on tobacco use or development of polysubstance use patterns. This study provides reassurance that legalization increases cannabis use without worsening tobacco or co-use patterns.

The numbers in context

9,003 participants in 2017; cannabis use +3.3%; tobacco use -1.9%; co-use +0.2% (not significant); recreational legalization 1.13x larger effect than medical; age range 18-94

How the study worked

Longitudinal study using a nationally representative web-based panel of 9,003 US adults surveyed in 2017, 2020, and 2021, with weighted adjusted binary logistic GEE models assessing legalization associations.

What this study cannot tell us

Self-reported substance use. Panel attrition (70% and 74% retention). Cannot account for all confounders. Binary cannabis use measure does not capture frequency or quantity changes.

How to read the evidence

Nationally representative longitudinal panel with appropriate modeling, though panel attrition and self-report are limitations.

When this study was published

Published in 2024 with 2017-2021 data.

The bigger picture

This is important for policy because it suggests that cannabis legalization's effects are cannabis-specific rather than driving broader substance use changes. The tobacco decline continuing during cannabis expansion challenges the 'gateway' narrative.

Questions still open

Will longer-term legalization eventually affect co-use patterns?
Does legalization change the demographic profile of cannabis users over time?

Common questions

Does cannabis legalization increase tobacco use?

No. This study found tobacco use continued declining in states that legalized cannabis, with no spillover effect.

Does legalization increase cannabis use?

Yes. Both medical and recreational legalization were associated with increased cannabis use, with recreational having a slightly larger effect.

Read the original research

Cannabis legalization and changes in cannabis and tobacco/nicotine use and co-use in a national cohort of U.S. adults during 2017-2021.

The International journal on drug policy, 134, 104618

View on PubMed ↗Publisher’s paper ↗

Citation

Pravosud, Vira; Glantz, Stanton; Keyhani, Salomeh; Ling, Pamela M; Lempert, Lauren K; Hoggatt, Katherine J; Hasin, Deborah; Nguyen, Nhung; Graham, Francis Julian L; Cohen, Beth E. (2024). Cannabis legalization and changes in cannabis and tobacco/nicotine use and co-use in a national cohort of U.S. adults during 2017-2021.. The International journal on drug policy, 134, 104618. https://doi.org/10.1016/j.drugpo.2024.104618