Background:Recreational cannabis legalization has become more prevalent over the past
decade, increasing the need to understand its impact on downstream
health-related outcomes. Although prior reviews have broadly summarized
research on cannabis liberalization policies (including decriminalization
and medical legalization), directed efforts are needed to synthesize the
more recent research that focuses on recreational cannabis legalization
specifically. Thus, the current review summarizes existing studies using
longitudinal designs to evaluate impacts of recreational cannabis
legalization on cannabis use and related outcomes.Method:A comprehensive bibliographic search strategy revealed 61 studies published
from 2016 to 2022 that met criteria for inclusion. The studies were
predominantly from the United States (66.2%) and primarily utilized
self-report data (for cannabis use and attitudes) or administrative data
(for health-related, driving, and crime outcomes).Results:Five main categories of outcomes were identified through the review: cannabis
and other substance use, attitudes toward cannabis, health-care utilization,
driving-related outcomes, and crime-related outcomes. The extant literature
revealed mixed findings, including some evidence of negative consequences of
legalization (such as increased young adult use, cannabis-related healthcare
visits, and impaired driving) and some evidence for minimal impacts (such as
little change in adolescent cannabis use rates, substance use rates, and
mixed evidence for changes in cannabis-related attitudes).Conclusions:Overall, the existing literature reveals a number of negative consequences of
legalization, although the findings are mixed and generally do not suggest
large magnitude short-term impacts. The review highlights the need for more
systematic investigation, particularly across a greater diversity of
geographic regions.