Marijuana Legalization Was Linked to Lower Adult Tobacco Use, but the Evidence Remains Mixed

A 2023 study found little evidence that recreational marijuana legalization increases adult tobacco use. Instead, researchers reported small, delayed declines in some measures of tobacco consumption, particularly cigarette and electronic nicotine-delivery-system use.

Published in the Journal of Health Economics, the study analyzed state policy changes alongside data from four nationally representative sources, including the Population Assessment of Tobacco and Health, the National Survey on Drug Use and Health, the Behavioral Risk Factor Surveillance System, and the Current Population Survey Tobacco Use Supplement. The authors used dynamic difference-in-differences and hazard models to compare changes in states that adopted recreational marijuana laws with changes in states that had not.

The study found that legalization was associated with an increase of roughly two percentage points in past-month marijuana use among adults. That increase was not accompanied by a comparable rise in tobacco use. In the short term, recreational marijuana laws had little measurable effect on overall tobacco consumption. Over the longer term, however, the researchers found some evidence of a decline—generally in the range of about 0.5 to 2 percentage points.

In the National Survey on Drug Use and Health data, tobacco-use reductions were more apparent after three or more years. Adult tobacco use declined by approximately 1.4% to 2.7%, while cigarette use fell by about 1.1% to 1.3%. The researchers also found evidence of a delayed reduction in electronic nicotine-delivery-system use. The effects were concentrated among men and in states where legalization was followed by the opening of recreational dispensaries, a pattern the authors said was consistent with cannabis replacing tobacco for some adults.

The paper estimated that, if the observed reduction in smoking prevalence were applied nationally, as many as 5.1 million fewer people might smoke cigarettes. Using previously estimated smoking-related healthcare costs, the authors calculated potential savings of about $10.2 billion annually. That figure is a model-based projection, not a measured reduction in healthcare spending.

The findings do not show that marijuana legalization causes people to quit smoking, nor do they establish that cannabis is a safer substitute for tobacco. The study was observational, and most states that later legalized recreational marijuana had previously adopted medical marijuana laws. As a result, the estimated recreational-law effects may partly reflect longer-term effects of medical legalization or other differences between states.

Later research has produced a more qualified picture. A 2025 longitudinal study using PATH data found that recreational cannabis legalization was associated with higher cannabis use, no significant change in cigarette use, and a modest increase in electronic nicotine-delivery-system use after five years. Together, the studies provide little support for the claim that legalization causes a large increase in cigarette smoking, but they do not establish a consistent nationwide decline in tobacco use.

That distinction matters because tobacco smoking remains a major cause of preventable disease and death. The evidence to date suggests that cannabis legalization and tobacco use may interact differently across products, populations, and time periods. Continued monitoring is needed, particularly as commercial cannabis markets expand and more people use noncombustible cannabis products.

Read the original 2023 study in PubMed, or see the 2025 longitudinal analysis published in JAMA Network Open.