Medical Marijuana Laws and Substance Induced Deaths: Evidence from the U.S

This paper explores the relationship between medical marijuana laws and substance induced deaths. The relationship between marijuana and alcohol empirically remains unclear; one strand of the literature shows the substitute relationship while another reveals the complementary relationship. In a similar vein, gateway drug hypothesis (i.e., marijuana consumption results in more harmful drug use) has been subject to empirical analyses, and yet proponents and opponents of the hypothesis have been often unclear about what policies it entails. That is, it is argued that a policy aims to reduce the risk of exposure to marijuana in order to prevent the use of other illicit drugs. On the other hand, one would claim that the problem lies in the nature of the illicit drug market where marijuana and other illicit drugs are simultaneously provided and supplied. Using state level panel data from Centers for Disease Control and Prevention and other data sources (1999-2010), I estimate the effects of medical marijuana laws on alcohol-induced deaths and cocaine-induced deaths. Empirical results show that medical marijuana laws result in an increase in alcohol-induced deaths, suggesting that there is a complementary relationship between marijuana and alcohol. In contrast, medical marijuana laws lead to a reduction in cocaine-induced deaths. The results shed light on understanding the complicated relationship between marijuana and substances in the sense that availability of substances plays a critical role in the gateway drug hypothesis. Alcohol is provided in a formal/ legal market whereas cocaine can be only supplied in an informal/ illicit market. It is therefore suggested that if such drug related policies change the way drug markets function and results in drug market separation, illicit drug induced deaths can be reduced.