Panel Paper: The Effects of Medical Marijuana Market Growth on Alcohol- and Opioid-Related Health Consequences

Thursday, November 8, 2018
Wilson A - Mezz Level (Marriott Wardman Park)

*Names in bold indicate Presenter

Rosanna Smart, RAND Corporation

Alongside dramatic growth in opioid mortality over the past 15 years, there has been increased interest in the potential role of marijuana as an alternative to opioid analgesics for treatment of chronic pain. While recent studies have suggested that the passage of medical marijuana laws, now present in more than half of U.S. states, is associated with reduced rates of opioid analgesic overdose and opioid prescribing, these studies have generally relied on binary measures of marijuana policy or policy components with limited consideration of how these policy changes translate to changes in actual access to medical marijuana or participation in medical marijuana markets. This paper contributes toward understanding the potential consequences of marijuana liberalization policies by studying how growth in the legal market for medical marijuana (proxied for by the share of adults registered as medical marijuana users) affects traffic fatalities and deaths related to alcohol and opioid poisonings. By collecting new data on per capita registered medical marijuana patient rates, I first investigate how state medical marijuana supply provisions and changes in federal enforcement interact to affect the size of this legal market. Using state-level outcome data from the National Survey of Drug Use and Health (NSDUH), the Fatal Accident Reporting System (FARS), and CDC WONDER, I then use difference-in-difference and instrumental variables approaches to study how illicit marijuana use and health externalities due to use of other substances respond to changes in legal medical marijuana availability. Recognizing potential differences in the mechanisms by which the legal market affects youths and adults, as well as potential age heterogeneity in the elasticity of substitution, I pay particular attention to differences in these outcomes by age.