Association for Public Policy Analysis & Management

The public health and safety effects of legalized medical and recreational marijuana have been the source of much debate – and much research. Analyses suggest that state regulation of marijuana outlets (particularly medical marijuana dispensaries) is a key factor in how marijuana laws affect public health indicators, particularly overdose from opioids and other drugs. Because these studies rely on state-level policies, they cannot account for variation in the availability of marijuana both within states that allow marijuana outlets and across states with similar marijuana laws. However, anecdotal evidence suggests that states with seemingly similar laws may in practice have a vastly different number of marijuana outlets, and outlets are not evenly distributed within states that allow them. Unless this variation is taken into account, the public health effects of legalizing medical and recreational marijuana cannot be fully understood. In this paper, I evaluate the impact of state-licensed marijuana outlets on opioid-related outcomes. The location and licensing date of marijuana outlets are obtained through administrative data from states that have always required marijuana outlets to be licensed, and where state law permits the release of this information. These data are then used to construct local measures of exposure to state-licensed marijuana outlets, based on the percentage of each locality within a 25-mile radius of a state-licensed marijuana outlet. I use difference-in-differences analysis to estimate the effects on outcomes related to opioid use, accounting for other aspects of state law. Outcomes of interest include county-level opioid prescribing data (from the QuintilesIMS Transactional Data Warehouse, as released by the Centers for Disease Control), CBSA-level treatment admissions (from SAMHSA’s Treatment Episode Data Set), and arrests for opium/cocaine arrests and possession (from the Uniform Crime Reports). This analysis provides a more nuanced picture of the public health and safety impact of state-licensed marijuana, and will assist policymakers in understanding the risks and benefits of marijuana in their communities.