Kennedy Krieger Institute and Johns Hopkins University School of Medicine, Baltimore, Maryland.
Harvard Medical School, Boston, Massachusetts.
J Am Acad Child Adolesc Psychiatry. 2024 Nov;63(11):1084-1113. doi: 10.1016/j.jaac.2024.02.016. Epub 2024 Mar 27.
Dramatic changes in state-level cannabis laws (CL) over the past 25 years have shifted societal beliefs throughout the United States, with unknown implications for youth. In the present study, we conducted an updated systematic review and meta-analysis examining estimated effects of medical cannabis legalization (MCL) and recreational cannabis legalization (RCL) on past-month cannabis use among US youth.
A systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, followed by a subsequent meta-analysis investigating the associations between state-level cannabis laws (ie, MCL vs non-MCL, and RCL vs non-RCL) and past-month cannabis use prevalence among US adolescents and young adults. Supplemental analyses examined age-group effects and design-related factors.
Our search identified 4,604 citations, 34 and 30 of which were included in qualitative and quantitative analyses, respectively. Meta-analysis of MCL studies identified no significant association between MCL and change in past-month youth cannabis use (odds ratio [OR] = 0.981, 95% CI = 0.960, 1.003). Meta-analysis of RCL studies showed significantly increased odds of past-month cannabis use (OR = 1.134, 95% CI = 1.116-1.153). Meta-analysis of more recent studies, however, showed a significantly increased odds of past-month cannabis use among both adolescents and young adults (OR = 1.089, 95% CI = 1.015,1.169, and OR = 1.221, 95% CI = 1.188,1.255, respectively).
Cannabis legalization has complex and heterogenous effects on youth use that may differ across law types. Our meta-analytic results showed modest positive effects of RCL on past-month cannabis use (more so in young adults than in adolescents) and minimal effects of MCL on these outcomes in US youth. Given the shift toward recreational legalization, additional focus on RCL effects is warranted.
Cannabis laws have changed dramatically throughout the United States over the past 25 years. It is important to determine if medical or recreational cannabis legalization are associated cannabis use in youth. The authors conducted a systematic review and meta-analysis to investigate the associations between state-level cannabis laws and past-month cannabis use in adolescents and young adults. The authors identified 64 articles and found that recreational cannabis laws were associated with a modest but significant higher odds of past-month cannabis use. In contrast, medical cannabis laws were not associated with past-month youth cannabis use. Analysis of more recent studies suggested a rise in cannabis use among youth. The authors conclude that further research is needed to better understand the impact of recreational cannabis legalization on youth.
在过去的 25 年中，州级大麻法律（CL）发生了巨大变化，这在美国各地改变了社会观念，对年轻人产生了未知的影响。在本研究中，我们进行了一项更新的系统评价和荟萃分析，以研究医用大麻合法化（MCL）和娱乐性大麻合法化（RCL）对美国青少年过去一个月大麻使用的估计影响。
按照系统评价和荟萃分析的首选报告项目（PRISMA）指南进行系统评价，随后进行荟萃分析，研究州级大麻法律（即 MCL 与非 MCL，以及 RCL 与非 RCL）与美国青少年和年轻人过去一个月大麻使用流行率之间的关联。补充分析检查了年龄组效应和设计相关因素。
我们的搜索确定了 4604 条引文，其中 34 条和 30 条分别纳入了定性和定量分析。MCL 研究的荟萃分析发现，MCL 与青少年过去一个月大麻使用变化之间没有显著关联（比值比 [OR] = 0.981，95%置信区间 [CI] = 0.960，1.003）。RCL 研究的荟萃分析表明，过去一个月大麻使用的可能性显著增加（OR = 1.134，95%CI = 1.116-1.153）。然而，对更新研究的荟萃分析表明，青少年和年轻人过去一个月大麻使用的可能性均显著增加（OR = 1.089，95%CI = 1.015，1.169，和 OR = 1.221，95%CI = 1.188，1.255，分别）。
大麻合法化对年轻人的使用产生了复杂且异质的影响，其影响可能因法律类型而异。我们的荟萃分析结果显示，RCL 对过去一个月大麻使用有适度的积极影响（在年轻人中比在青少年中更为明显），而 MCL 对美国年轻人的这些结果几乎没有影响。鉴于向娱乐性合法化的转变，有必要进一步关注 RCL 的影响。
