Medical marijuana laws and adolescent marijuana use in the USA from 1991 to 2014: results from annual, repeated cross-sectional surveys
Medical marijuana laws and adolescent marijuana use in the USA from 1991 to 2014: results from annual, repeated cross-sectional surveys
复制标题
DOI：
10.1016/s2215-0366(15)00217-5
复制
发表时间：
2015-07-01
影响因子：
64.3
通讯作者：
Feng, Tianshu
中科院分区：
文献类型：
--
作者：
Hasin, Deborah S.;Wall, Melanie;Feng, Tianshu
背景：青少年使用大麻与不良后果有关，因此确定青少年使用大麻的潜在因素对公共卫生具有重要意义。美国各州法律允许医用大麻与青少年使用大麻之间的关系一直存在争议。这样的法律可能会传达一种信息，即大麻的可接受性在通过后很快就会增加，即使实施被推迟，或者法律对大麻的使用进行了狭隘的限制。我们使用了美国24年的国家数据来检验各州医用大麻法律与青少年使用大麻之间的关系。“监测未来”研究采用多阶段、随机抽样和置换设计，每年对大约400所学校的8年级、10年级和12年级学生（分别为13-14岁、15-16岁和17-18岁）进行全国性调查。学生们完成自我管理的问卷，其中包括有关大麻使用的问题。我们分析了1991年至2014年间调查的1098 270名青少年的数据。这项分析的主要结果是在过去30天内使用大麻的情况。我们使用青少年嵌套在状态中的多水平回归模型来检验两个问题。第一个问题是，在2014年之前通过医用大麻法的州，大麻的总体使用量是否更高。第二个是在医用大麻法律通过后，使用大麻的风险是否发生了变化。控制协变量包括个人、学校和州一级的特征。在2014年之前通过医用大麻法的州，大麻的使用比其他州更普遍（调整后的患病率为15.87% vs 13.27%；调整后的优势比[OR] 1.27, 95% CI 1.07-1.51; p=0.0057）。然而，各州在通过医用大麻法律前使用大麻的风险与通过医用大麻法律后使用大麻的风险无显著差异（调整患病率16.25% vs 15.45%；调整OR 0.92, 95% CI 0.82-1.04; p=0.185）。敏感性分析的结果总体上是稳健的，包括将大麻使用重新定义为前一年的任何使用或使用频率，并重新分析医用大麻法律的延迟效应或药房规定的变化。我们的研究结果与之前的证据一致，表明州医用大麻法律的通过并没有增加青少年对大麻的使用。然而，总体而言，在通过此类法律的州，青少年使用大麻的比例高于其他州。除医用大麻法律外，国家层面的风险因素可能对大麻的使用和医用大麻法律的通过都有影响，这些因素值得调查。
Background Adolescent use of marijuana is associated with adverse later effects, so the identification of factors underlying adolescent use is of substantial public health importance. The relationship between US state laws that permit marijuana for medical purposes and adolescent marijuana use has been controversial. Such laws could convey a message about marijuana acceptability that increases its use soon after passage, even if implementation is delayed or the law narrowly restricts its use. We used 24 years of national data from the USA to examine the relationship between state medical marijuana laws and adolescent use of marijuana.Methods Using a multistage, random-sampling design with replacement, the Monitoring the Future study conducts annual national surveys of 8th, 10th, and 12th-grade students (modal ages 13-14, 15-16, and 17-18 years, respectively), in around 400 schools per year. Students complete self-administered questionnaires that include questions on marijuana use. We analysed data from 1 098 270 adolescents surveyed between 1991 and 2014. The primary outcome of this analysis was any marijuana use in the previous 30 days. We used multilevel regression modelling with adolescents nested within states to examine two questions. The first was whether marijuana use was higher overall in states that ever passed a medical marijuana law up to 2014. The second was whether the risk of marijuana use changed after passage of medical marijuana laws. Control covariates included individual, school, and state-level characteristics.Findings Marijuana use was more prevalent in states that passed a medical marijuana law any time up to 2014 than in other states (adjusted prevalence 15.87% vs 13.27%; adjusted odds ratio [ OR] 1.27, 95% CI 1.07-1.51; p=0.0057). However, the risk of marijuana use in states before passing medical marijuana laws did not differ significantly from the risk after medical marijuana laws were passed (adjusted prevalence 16.25% vs 15.45%; adjusted OR 0.92, 95% CI 0.82-1.04; p=0.185). Results were generally robust across sensitivity analyses, including redefining marijuana use as any use in the previous year or frequency of use, and reanalysing medical marijuana laws for delayed effects or for variation in provisions for dispensaries.Interpretation Our findings, consistent with previous evidence, suggest that passage of state medical marijuana laws does not increase adolescent use of marijuana. However, overall, adolescent use is higher in states that ever passed such a law than in other states. State-level risk factors other than medical marijuana laws could contribute to both marijuana use and the passage of medical marijuana laws, and such factors warrant investigation.