UCLA

Over half of the US states have adopted "medical marijuana" laws (MMLs), and 58% of Americans now favor marijuana legalization. Despite public support, federal law continues to prohibit the use and sale of marijuana due to public health concerns of increased dependence and abuse, youth access, and drugged driving. These essays contribute toward understanding the likely health consequences of marijuana liberalization using evidence from MMLs.

Chapter 1 -- Growing Like Weed: Explaining Variation in Medical Marijuana Market Size provides a comprehensive analysis of the determinants of growth in legal medical marijuana markets. Newly collected data on medical marijuana patient registration rates shows that there is substantial heterogeneity in medical marijuana participation over time and across states. This variation is primarily driven by the combined effects of federal enforcement policy and state supply restrictions on legal production costs. Chapter 2 -- The Kids Aren't Alright: Effects of Medical Marijuana Market Growth on Marijuana Use then studies the effect of growth in legal medical marijuana markets on recreational use. Findings show that expansion of legal medical marijuana market size significantly increases the prevalence of recreational cannabis use by both adults and adolescents. Reaching the median state's legal market size would increase the prevalence of marijuana use in the past month by 6% for adolescents aged 12-17, by 9% for 18-25 year-olds, and by 18% for adults over age 25.

The welfare implications of these changes largely depend on the externalities and internalities associated with marijuana use. To study this, Chapter 3 -- On the Health Consequences of Increased Medical Marijuana Access examines the effects of increased marijuana availability on traffic fatalities and mortality related to opioid and alcohol poisonings. In the aggregate, greater medical marijuana access decreases mortality from these causes. However, the aggregate effect masks an important welfare trade-off generated by age differences in the elasticity of substitution between marijuana and alcohol. For adults aged 45-64, greater marijuana availability reduces mortality related to alcohol and opioid poisonings by 7-11% and 12-16% respectively. In contrast, for youths aged 15-20, marijuana access generates negative externalities in the form of a 6% increase in traffic fatalities, with large and significant effects on alcohol- and cannabis-related accidents.