Thursday, May 15, 2025
5/15/2025
The Effects of Cannabis Legalization and Persistent Use: A Longitudinal Study of Two Twin Cohorts - PROJECT ABSTRACT Recreational cannabis legalization (RCL) is swiftly expanding in the United States. Ideally, such policy shifts are informed by evidence; however, little is known about the effects of RCL. This is particularly true for long- term effects. Data from states that were the first to legalize cannabis can help understand RCL’s long-term effects. With public opinion indicating that further RCL expansion is likely, it is imperative to clearly understand its public health consequences. Our original grant suggested that adults living in RCL states used cannabis 20% more frequently (than those in non-RCL states) but had virtually no other psychosocial consequences. However, increasing evidence suggests that cannabis use is most consequential when it is frequent and persistent. In the context of this literature, it is worth noting that our original grant assessed behavior within approximately five years of legalization. It is unclear whether continued access to cannabis in RCL environments increases persistent use, leading to negative consequences. We propose a renewal grant to examine the long-term impact of RCL in approximately 4,500 participants from two large, prospective twin cohorts in Colorado (CO; full RCL since 2014) and Minnesota (MN; RCL passed in 2023, dispensaries expected to open in 2024). Both CO and MN participants have been assessed at least three times before RCL began in CO (adolescence, emerging adulthood, young adulthood) and twice since RCL began in CO. The proposed project would collect the third post-RCL assessment in CO and the first since RCL began in MN. We will leverage this study design to control important familial confounds related to cannabis use and its potential consequences. Further, we will incorporate the longitudinal nature of these cohorts to control prior behavior (e.g., cannabis use, mental health) while examining the effects of RCL. Thus, we will use these data to address whether years of RCL access affect cannabis use, alcohol use, mental health, and physical health (Aim 1). We hypothesize that having more years of RCL access is associated with greater cannabis use and consequences. Further, we will determine whether pre-RCL mental and physical health problems predict increased post-RCL cannabis use (Aim 2). This aim is based on evidence, including our preliminary data, that suggest health problems are a common motive for cannabis use. Thus, we hypothesize that pre-RCL health problems are associated with greater post-RCL cannabis use. Finally, we will identify individual differences uniquely related to post-RCL cannabis use and consequences (Aim 3). We hypothesize that post-RCL cannabis and its consequences are associated with greater perceived cannabis benefits, greater ease of access, and personality factors that may have impeded cannabis use in non-legal contexts (higher harm avoidance, lower rule-breaking). In summary, this study will equip key stakeholders with well-controlled, rich evidence on the consequences of RCL.
HHS’ Tracking Accountability in Government Grants System (TAGGS) website provides access to detailed descriptions of grants, loans, aggregated direct payments and other types of financial assistance awarded by the HHS Operating Divisions (OPDIVs) and the Office of the Secretary Staff Divisions (STAFFDIVs).