Cerdá Magdalena, Wall Melanie, Feng Tianshu, Keyes Katherine M, Sarvet Aaron, Schulenberg John, O'Malley Patrick M, Pacula Rosalie Liccardo, Galea Sandro, Hasin Deborah S
Department of Emergency Medicine, University of California Davis School of Medicine, Sacramento.
Department of Psychiatry, Columbia University Medical Center, New York, New York3New York State Psychiatric Institute, New York4Department of Biostatistics, Mailman School of Public Health, Columbia University, New York, New York.
JAMA Pediatr. 2017 Feb 1;171(2):142-149. doi: 10.1001/jamapediatrics.2016.3624.
Historical shifts are occurring in marijuana policy. The effect of legalizing marijuana for recreational use on rates of adolescent marijuana use is a topic of considerable debate.
To examine the association between the legalization of recreational marijuana use in Washington and Colorado in 2012 and the subsequent perceived harmfulness and use of marijuana by adolescents.
DESIGN, SETTING, AND PARTICIPANTS: We used data of 253 902 students in eighth, 10th, and 12th grades from 2010 to 2015 from Monitoring the Future, a national, annual, cross-sectional survey of students in secondary schools in the contiguous United States. Difference-in-difference estimates compared changes in perceived harmfulness of marijuana use and in past-month marijuana use in Washington and Colorado prior to recreational marijuana legalization (2010-2012) with postlegalization (2013-2015) vs the contemporaneous trends in other states that did not legalize recreational marijuana use in this period.
Perceived harmfulness of marijuana use (great or moderate risk to health from smoking marijuana occasionally) and marijuana use (past 30 days).
Of the 253 902 participants, 120 590 of 245 065(49.2%) were male, and the mean (SD) age was 15.6 (1.7) years. In Washington, perceived harmfulness declined 14.2% and 16.1% among eighth and 10th graders, respectively, while marijuana use increased 2.0% and 4.1% from 2010-2012 to 2013-2015. In contrast, among states that did not legalize recreational marijuana use, perceived harmfulness decreased by 4.9% and 7.2% among eighth and 10th graders, respectively, and marijuana use decreased by 1.3% and 0.9% over the same period. Difference-in-difference estimates comparing Washington vs states that did not legalize recreational drug use indicated that these differences were significant for perceived harmfulness (eighth graders: % [SD], -9.3 [3.5]; P = .01; 10th graders: % [SD], -9.0 [3.8]; P = .02) and marijuana use (eighth graders: % [SD], 5.0 [1.9]; P = .03; 10th graders: % [SD], 3.2 [1.5]; P = .007). No significant differences were found in perceived harmfulness or marijuana use among 12th graders in Washington or for any of the 3 grades in Colorado.
Among eighth and 10th graders in Washington, perceived harmfulness of marijuana use decreased and marijuana use increased following legalization of recreational marijuana use. In contrast, Colorado did not exhibit any differential change in perceived harmfulness or past-month adolescent marijuana use following legalization. A cautious interpretation of the findings suggests investment in evidence-based adolescent substance use prevention programs in any additional states that may legalize recreational marijuana use.
大麻政策正在发生历史性转变。娱乐用大麻合法化对青少年大麻使用率的影响是一个备受争议的话题。
研究2012年华盛顿州和科罗拉多州娱乐用大麻合法化与随后青少年对大麻的感知危害及使用情况之间的关联。
设计、背景和参与者：我们使用了2010年至2015年来自“监测未来”（Monitoring the Future）的253902名八年级、十年级和十二年级学生的数据，这是一项对美国本土中学学生进行的全国性年度横断面调查。差异估计法比较了娱乐用大麻合法化之前（2010 - 2012年）和合法化之后（2013 - 2015年）华盛顿州和科罗拉多州大麻使用感知危害及过去一个月大麻使用情况的变化，与同期未将娱乐用大麻合法化的其他州的趋势。
大麻使用的感知危害（偶尔吸食大麻对健康有很大或中等风险）和大麻使用情况（过去30天内）。
在253902名参与者中，245065名（49.2%）中的120590名是男性，平均（标准差）年龄为15.6（1.7）岁。在华盛顿州，八年级和十年级学生中，大麻使用的感知危害分别下降了14.2%和16.1%，而从2010 - 2012年到2013 - 2015年，大麻使用分别增加了2.0%和4.1%。相比之下，在未将娱乐用大麻合法化的州中，八年级和十年级学生中，大麻使用的感知危害分别下降了4.9%和7.2%，同期大麻使用分别下降了1.3%和0.9%。比较华盛顿州与未将娱乐用毒品合法化的州的差异估计表明，这些差异在大麻使用的感知危害方面具有统计学意义（八年级学生：百分比[标准差]，-9.3[3.5]；P = 0.01；十年级学生：百分比[标准差]，-9.0[3.8]；P = 0.02）以及大麻使用方面（八年级学生：百分比[标准差]，5.0[1.9]；P = 0.03；十年级学生：百分比[标准差]，3.2[1.5]；P = 0.007）。在华盛顿州的十二年级学生中或科罗拉多州的任何三个年级中，在大麻使用的感知危害或大麻使用方面均未发现显著差异。
在华盛顿州的八年级和十年级学生中，娱乐用大麻合法化后，大麻使用的感知危害降低，大麻使用增加。相比之下，科罗拉多州在合法化后，在大麻使用的感知危害或过去一个月青少年大麻使用方面未表现出任何差异变化。对这些发现的谨慎解读表明，在任何可能将娱乐用大麻合法化的其他州，应投资基于证据的青少年物质使用预防项目。
