Association for Public Policy Analysis & Management

March 2018

Previous work has shown that recent medical marijuana laws have had spillover effects on recreational markets, impacting adult recreational marijuana use including near daily use (Hasin et al., 2015; Pacula et al., 2015; Wen et al., 2015). However, no work has yet been done to explore the extent to which these policies influence the duration of marijuana use or quitting behavior. Duration is important for at least two reasons. First, most of the identified health and social impacts associated with marijuana use are associated with persistent frequent use, not simply any use of cannabis. Second, evidence from the tobacco literature clearly demonstrates that tobacco control influence smoking initiation and cessation decisions differentially than they do static measures of use, including prevalence (DeCicca et al., 2008). The decision to quit marijuana use may be delayed in response to medical marijuana policies if the opening of dispensaries reduces the time and monetary cost associated with obtaining marijuana or if they reduce the legal risk of obtaining or using it.

In this paper, we exploit cross-state variation in the timing of dispensary openings and their legal protection to explore the extent to which changes in the cost of marijuana influence quitting behavior. We link information on dispensary openings and legal protections of them to self-reported longitudinal data from the 1997-2011 National Longitudinal Survey of Youth, which allows us to identify trajectories of use over multiple years. We examine the decision to quit by gender and ethnicity, in light of differences in legal risks of arrest particularly for marijuana (Geller and Fagan, 2010; Nguyen and Reuter, 2012; Ramchand et al., 2006). We find that, irrespective of race, there is no evidence that women change their quitting behavior in response to the opening of medical marijuana dispensaries or their legal protection. For males, however, we find that white males reduce their quitting behavior in response to the opening of a medical marijuana dispensary (by 29%) but not their legal protection. Blacks and Hispanic males, on the other hand, do not respond to dispensaries opening; they only respond to dispensaries being legally protected, in which case Blacks reduce their quit behavior by 68% and Hispanics reduce their quitting by 26%. In general, we conclude that consumption duration among men is sensitive to the opening of marijuana markets, but it is the legal protection of these markets that influence minorities more so then their simple presence.

[i] Department of Economics, University of Melbourne, Parkville, Australia and IZA: email: jenny.williams@unimelb.edu.au.

[ii] RAND Drug Policy Research Center, Santa Monica, 1776 Main St., P.O. Box 2138 and National Bureau of Economic Research. Email: pacula@rand.org.

[iii] RAND Drug Policy Research Center, Santa Monica, 1776 Main St., P.O. Box 2138. Email: rsmart@rand.org.