Association of Cannabis Legalization with Cannabis Positive Drug Screening in US Veterans

Abstract Background: Although cannabis legalization is associated with increases in self-report cannabis use, biological measures of cannabis use are needed to address potential bias introduced by improved self-reporting of cannabis use in states enacting medical cannabis laws (MCL) and recreational cannabis laws (RCL). Objective: Quantify the role of MCL and RCL enactment in cannabis positive urine drug screen (UDS) prevalence among Veterans Health Administration (VHA) emergency department (ED) patients from 2008 to 2019. Design: Staggered-adoption difference-in-difference analysis were used to