Impact of Changing Cannabis Laws on Cannabis Use Disorders, Serious Mental Illness, and Mortality Outcomes in US Youth: A Narrative Review

Abstract: Youth cannabis use is a major public health crisis. Cannabis laws carry significant health implications for American youth. Relaxing of these laws – through decriminalization, medical and recreational legalization – by a majority of states in the United States (US) over the past 25 years has dramatically shifted societal perceptions and adult use. How cannabis policy changes have affected the population-wide health of US youth and downstream public health implications of cannabis laws remain topics of significant debate. Cannabis is the most commonly used federally-illicit drug by US adolescents and the main drug for which US teens obtain substance use treatment. Adolescent cannabis use is associated with negative long-term consequences for mental health, risk-taking behaviors, and academic/job achievement. As of January 2023, 37 states and the District of Columbia (DC) have enacted medical cannabis laws; of these, 21 states and DC have recreational cannabis laws. Multiple studies have assessed the association between cannabis laws and youth cannabis use; results indicate mostly null effects for medical laws and mixed effects for recreational laws. Little is known about the effects of cannabis laws on mental health and mortality outcomes for American youth. Methodological limitations have made the interpretation of this literature difficult. This article presents a narrative review of current scientific literature investigating the impact of changing cannabis policies on cannabis and other drug use, mental health, and mortality outcomes in US youth. Implications are framed within a larger discussion on national trends in youth drug use, effects of adolescent cannabis exposure on health outcomes, and research-based policymaking.