This dissertation consists of three essays, each using applied econometric techniques to examine important questions within the field of health economics. These papers are concerned with identifying the causal effect of recreational cannabis laws on outcomes related to prescription drug utilization, mental health, and substance use. In the first chapter, I offer evidence of the relationship between recreational cannabis legalizations and suicide mortality. In the latter two chapters, I explore the relationship between recreational cannabis legalizations and consumer demand for prescription drugs. In chapter one, I investigate the causal effect of recreational cannabis access on suicide mortality. Using restricted-Access death certificate data from the CDC National Vital Statistics System (NVSS), I leverage variation in recreational cannabis law adoption to identify the causal effect on cannabis law adoption on suicides mortality. I find suggestive evidence that the legalization of recreational cannabis is associated with a reduction in suicide mortality for those aged 35 to 44. I fail to find a relationship between these cannabis policies and suicide mortality in any other groups. In the second chapter, which is joint work with Ashley C. Bradford, we examine the effect of recreational cannabis legalizations on the utilization of prescription drugs. Using a panel of administrative data on drug utilization in the Medicaid population, we identify a set of drugs which align with conditions treated with medical cannabis. Identification of the causal effect of the policy exploits variation in states' decisions to legalize cannabis for adult (recreational) use, in a difference-in-differences framework. We find that these laws reduce prescription drug utilization by 12 to 20 percent for the conditions considered, including those related to anxiety, depression, and pain management. In the third chapter, which is joint work with J. Catherine Maclean, W. David Bradford, and Coleman Drake, we assess the effect of recreational cannabis laws on opioid distribution. We use a panel of data on opioid distribution from the Automation of Reports and Consolidated Orders System (ARCOS) and exploit variation in the timing of recreational cannabis laws to identify the causal effect of these recreational cannabis law adoption on opioid distribution. We find no evidence that recreational cannabis laws are associated with changes in high potency opioid distribution, but we do present evidence that these laws are associated with 24-36 percent reductions in codeine distribution: a low potency opioid with a high misuse potential.