The Effects of Medical Marijuana Laws on Prescribed Opioids and Other Prescription Drugs

Abstract

More than half of the US population lives in a state that has adopted medical marijuana laws (MMLs). Studies show that most medical marijuana patients use marijuana for managing their pain with the overwhelming majority of them preferring it to opioids. Despite ongoing pro-marijuana policies and the growing trend of public acceptance, the evidence on how people change their prescription use due to the availability of marijuana as an alternative treatment is limited. Using the variations across state MMLs between 1996 and 2014 of Medical Expenditure Panel Survey (MEPS) this paper estimates the effects of MMLs on prescription drug utilization, with a focus on opioids. I find that MMLs lead to a $2.47 decrease in per person prescribed opioid spending among young adults (ages 18-39) over a year. Most of this decrease results from the intensive margin of use and MML states that allow home cultivation experience even larger decreases. Furthermore, the decreasing effects are persistent over time and they get stronger following the years of implementation. MMLs also decrease the number of opioid pill use among young adults. I do not find any discernible impact on older populations' opioid utilization. I then investigate the effects on other prescriptions for which marijuana can be a potential substitute and find the allowance of dispensaries is generally associated with decreases, although the effects depend on the the type of MML, the margin of use and age.