Kyra N. Farrelly · Substance Abuse Research and Treatment 2023 · systematic review of longitudinal studies · n=61 studies

The Impact of Recreational Cannabis Legalization on Cannabis Use and Associated Outcomes: A Systematic Review

Cited 144 times in the scientific literature.

Level 1 - systematic review of randomized trials

Systematic review of longitudinal studies (level assigned by design analogy for public health policy research).

OpenAlex W4376056030 · doi:10.1177/11782218231172054 · record verified 2026-08-26

What was done

A systematic review was conducted to evaluate longitudinal studies published between 2016 and 2022 assessing the impact of recreational cannabis legalization on cannabis use and downstream health and social outcomes. A bibliographic search identified 61 studies, predominantly from the United States (66.2%). Primary studies mostly utilized self-report measures (for cannabis use and attitudes) and administrative datasets (for health-care, driving, and crime outcomes).

What was found

The abstract reports no numerical effect sizes or statistical test results. Across five main outcome domains, findings were mixed: some studies reported increases in young adult cannabis use, cannabis-related health-care visits, and impaired driving, whereas minimal impacts were observed for adolescent cannabis use and overall substance use rates. Evidence for shifts in cannabis-related attitudes was mixed, with no evidence of large-magnitude short-term impacts overall.

Why it matters

This review synthesizes evidence specifically focused on recreational cannabis legalization rather than medical legalization or decriminalization, evaluating its short-term impacts on public health, safety, and consumption patterns.

Limits

No quantitative effect estimates or meta-analytic pooled values are provided in the abstract. Included literature relies substantially on self-report and administrative data, is geographically restricted primarily to the United States (66.2%), and reflects mixed findings with unclear long-term generalizability.

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