What topics does this cannabis study cover?

This study covers research on: Mental Health, Addiction.

Where was this research published?

Published in Substance use & misuse on August 26, 2026.

What legalization changes—and where public-health risks remain

Q: What did this research study find?

**Cannabis legalization reduced cannabis-specific enforcement**, particularly possession arrests, across the reviewed evidence.

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

Substance use & misuse • August 26, 2026 • Highly Relevant

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AI Summary

This systematic review examined research published from 2020–2025, drawing on 329 studies about cannabis legalization. Using PRISMA 2020 guidance alongside bibliometric mapping, topic modeling, and manual analysis, it found that legalization consistently reduced cannabis-specific enforcement, especially possession arrests. Adult cannabis use, legal purchasing, and perceived access generally increased, particularly in places with expanded retail markets.

The effects on young people and public health were more uneven. Adolescent prevalence did not rise uniformly, but lower perceived risk, more frequent use, edible exposure, accidental ingestion, emergency care, and cannabis use disorder-related outcomes emerged as concerns. Health harms were concentrated around intoxication, pediatric exposure, emergency visits, and selected mental-health issues. Legal markets also did not eliminate illicit supply, while road-safety findings varied depending on how crashes, toxicology, and impairment were measured. The review concludes that legalization is best understood as an ongoing regulatory process whose results depend heavily on market access, commercialization, enforcement choices, normalization, and public-health safeguards.

💡 Key Findings

Cannabis legalization reduced cannabis-specific enforcement, particularly possession arrests, across the reviewed evidence.

High

85%

Adult cannabis use, legal purchasing, and perceived access generally increased, especially after retail markets expanded.

High

80%

Adolescent prevalence did not increase uniformly, but youth and child risks included lower perceived risk, frequent use, edible exposure, accidental ingestion, and emergency care.

High

80%

Legal markets expanded without consistently displacing illicit supply; road-safety findings remained dependent on crash measures, toxicology, and definitions of impairment.

Good

75%

Legalization outcomes depend on regulatory design, including market access, commercialization, enforcement reallocation, normalization, and public-health protections.

High

85%

📄 Original Abstract

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.