Cannabis Legalization: A Systematic Review of Effects on Public Health, Criminal Justice, and Society, 2020-2025

Cannabis legalization has expanded across jurisdictions, but its effects remain difficult to interpret because studies examine different populations, policy models, and outcomes. This review synthesized evidence on legalization effects from 2020 to 2025.

Scopus was searched for English-language journal articles published from 2020 to 2025. After screening, 329 studies were included. The review followed PRISMA 2020 guidance and combined bibliometric mapping, LDA topic modeling, and manual content analysis. Findings were coded by domain and direction.

Evidence was strongest for reduced cannabis-specific enforcement, especially possession arrests. Adult cannabis use, legal purchasing, and perceived access generally increased, particularly where retail markets expanded. Adolescent prevalence did not increase uniformly, but youth and child risks appeared through lower perceived risk, higher-frequency use, edible exposure, accidental ingestion, emergency care, and cannabis use disorder-related outcomes. Health harms centered on emergency visits, intoxication, pediatric exposure, and selected mental-health concerns. Legal markets expanded, but illicit supply persisted where legal products were costly, inaccessible, or less competitive. Road-safety findings depended on crash measures, toxicology, and impairment definitions.

Legalization is best understood as a regulatory process whose effects depend on market access, commercialization, enforcement reallocation, normalization, public-health burden, and regulatory design.