Medical cannabis legalization and state-level prevalence of serious mental illness in the National Survey on Drug Use and Health (NSDUH) 2008–2015

Abstract

Although research has established a link between cannabis legalization and use, and cannabis use and mental health, the relationship between medical cannabis legalization and mental health remains uncharacterized. This analysis investigated the relationship between state medical cannabis laws (restrictive, i.e. covering a narrow set of medical conditions; or liberal, i.e. covering a broad range of medical conditions), whether the law permits patients to petition their physician to approve medical cannabis use for specific medical conditions, and state prevalence of serious mental illness (SMI) in the National Survey of Drug Use and Health 2008–2015. In a covariate-adjusted meta-regression, liberal laws were significantly associated with higher prevalence of SMI (Coeff = 0.003, SE = 0.001, p < .001). Restrictive laws (Coeff = 0.001, SE = 0.001, p = .285) and the ability to petition physician approval (Coeff = −0.001, SE = 0.001, p = .140) were non-significant. When added to the model, state past-year cannabis use was significantly associated with higher prevalence of SMI (Coeff = 0.037, SE = 0.015, p = .018), liberal laws remained significant (Coeff = 0.002, SE = 0.001, p = .015), and restrictive laws (Coeff = −0.0001, SE = 0.001, p = .945) and the ability to petition a physician (Coeff = 0.001, SE = 0.001, p = .290) remained non-significant. Medical cannabis laws are likely related to state mental health, and a higher prevalence of cannabis use partially explains this relationship.

Keywords:

• Cannabis
• serious mental illness
• mental illness
• cannabis legalization
• marijuana use
• state

Acknowledgements

We would like to thank Eric Otto Johnson for supporting our work on this paper.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Additional information

Funding

This research was funded by an internal RTI award.