Impact of Recreational and Medical Marijuana legalization on cannabis use disorders, serious mental illness, and mortality outcomes among Medicaid enrolled youth - ABSTRACT Adolescent and young adult (AYA) cannabis use is a major public health crisis. Implementation of state medical and recreational cannabis laws (MCL and RCL) have led to increased exposure to diverse cannabis products across the US. Adult use patterns have shifted dramatically as MCL and RCL have gone into effect in most US states in the past 27 years. Currently, 37 states and the District of Columbia (DC) have enacted MCL; of these, 21 states/DC have enacted RCL. These changes provide an opportunity to evaluate associations, positive and negative, with important population health outcomes in AYA. Cannabis is the most commonly used illicit drug by US AYA and it is the main drug for which US adolescents obtain substance use (SU) treatment. Cannabis use during AYA is associated with negative long-term consequences on mental health (MH) outcomes, risk-taking behaviors (eg, motor vehicle accidents), and academic/job achievement. No studies to date, however, have evaluated the impact of CL on AYA MH or mortality outcomes. Few studies have assessed the association between CL and cannabis use in AYA, and even fewer have examined whether aspects of CL, including the restrictiveness of various provisions included in CL (ie, details related to barriers to obtaining medical cannabis-such as covered diagnoses, the quantity that can be purchased, and how distribution is managed via dispensaries or private cultivation). Important evidence gaps remain regarding the associations between state CL and AYA health outcomes. The overarching goal of this NIDA R01 project is to characterize the associations of state-level MCL and RCL, including degree of CL restrictiveness and the effect of varying provisions, on changes in important population health outcomes including cannabis use disorder (CUD), serious mental illness, non-cannabis substance use disorder, suicide-related outcomes, all-cause mortality, and treatment utilization for SU and MH services, including prescription medication, in US AYA. Our central hypothesis is that CL will be associated with higher rates of CUD, serious mental illness, non-cannabis SU disorder, suicide related outcomes, and all-cause mortality, with less restrictive CL being associated with worse health outcomes. We will use a difference in difference (DID) quasi-experimental design, with CL, defined through MCL/RCL effective dates, serving as the main intervention of interest. We will use national Medicaid data from all 50 states and DC for the period 1/1/2000 to 12/31/2021 merged with National Death Index, SAMHSA service utilization, and state level covariate data. Our study population will include a 20% random sample of all US AYA (N=55 million). Medicaid-enrolled AYA have higher prevalence rates of MH/SU disorders and poorer physical and mental health outcomes compared to age matched peers; thus, they are a large population with high health risk, among whom the association between health and MCL and RCL are unknown. Multilevel models will be fit to obtain estimates of before vs. after changes among AYA in states enacting MCL and RCL compared to those in states with no CL, controlling for individual and state-level covariates, including co-occurring features that could impact outcomes. This study will provide rigorous evidence regarding associations between state CL implementation and AYA health outcomes.
