Multilevel Risk and Protective Factors Influencing Cannabis Use Among Adolescents and Young Adults in the United States: A Systematic Review.

Cannabis use among adolescents and young adults has become a significant public health concern in the United States (US), as it is associated with immediate and long-term effects on mental health, academic achievement, and social functioning. The purpose of this systematic review was to identify risk and protective factors contributing to cannabis use initiation and continuation among adolescents and young adults in the US. A search (January 2019 to September 2024) was conducted across CINAHL, Medline (OVID), and PubMed databases using PRISMA guidelines and relevant MeSH terms. Studies were included if they were peer-reviewed, quantitative, US-based, and involved youth ages 12-26. Fifteen studies met inclusion criteria and were critically appraised for quality. The Social Ecological Model guided analysis. Findings revealed that cannabis use is shaped by multi-level influences. At the individual level, older age, early initiation, lower perceived risk of harm, and polysubstance use were key risk factors. At the interpersonal level, peer influence, parental acceptance of cannabis use, and family structure played prominent roles, with peer disapproval and parental monitoring emerging as strong protective factors. At the community level, perceived neighborhood stress, social media exposure, and proximity to cannabis dispensaries contributed to increased use, while school connectedness and extracurricular involvement served as protective influences. At the societal level, cannabis legalization and lower socioeconomic status were associated with increased use and normalization of behavior. Gender disparities in use are narrowing, with similar rates reported among males and females. This review underscores the need for multi-level interventions that address peer and familial norms, promote public education to increase perceived harm, and account for environmental and policy contexts. Evidence-based strategies targeting individual, relational, community, and societal factors are essential to reduce cannabis use and mitigate its adverse effects among youth.