State medical marijuana laws and MTF teen marijuana use and attitudes since 1991

描述(由申请人提供)：自1996年以来，已有16个州通过了使医用大麻合法化的法律，其他州正在考虑这样的法律。由于几乎没有科学证据来证明这些快速变化的法律是否会导致青少年非法使用大麻(AMU)的增加，这个问题现在在很大程度上是一个有争议的问题。最近，使用来自两项全国调查的数据，我们显示，拥有医用大麻法律的州(MML)的青少年(Wall等人，2011年)和成年人(Cerda等人，正在出版)的大麻使用率明显高于其他州。这些结果强调了对MML和AMU进行进一步研究的重要性，但它们并不能解决争论，因为这样做需要解释我们在患有MML的州发现的更高的AMU。我们建议研究四种可供选择的解释：(A)MML的通过直接增加AMU~(B)MML的通过间接增加AMU，通过更有利的态度和/或更多的可获得性介导~(C)MML和AMU相关，因为更高的使用率和更有利的态度已经表现出通过MML的州的特征，或者(D)存在一个互惠的过程，使得使用率更高和态度更有利的州通过MML，从而进一步增加AMU的风险。我们将使用自1991年以来每年从监测未来(MTF)调查中收集的100万青少年的时间序列数据进行这项研究。由于多年来方法(例如程序、问卷)的谨慎一致性，MTF是现有的最大数据集，其中包含关于MML和AMU的相关信息，包括关键感兴趣的潜在调解人，包括与大麻有关的态度(例如，不赞成~感知的风险)和感知的大麻可获得性。在整个研究过程中，新的数据将被 增加了州MML的变化，以及MTF每年额外调查的约47,000名学生。数据将使用最先进的统计方法(具有后分层的多水平回归建模)进行分析。我们将检查年度州MML和AMU，测试相对于国家趋势的州内趋势，并探索不同的时间滞后。分析将 纳入个人层面的青少年态度和感知的可获得性作为潜在的中介，以及来自人口普查和其他数据来源的州一级定义的变量(例如，人口对大麻的态度、州人口构成、大麻逮捕率)作为MML通过的潜在决定因素。此外，我们将探索州MML的变化(例如，法律允许的范围)是否会影响结果，性别、社会经济地位和种族/民族是否会调节MML和AMU之间的关系，以及关系是特定于大麻还是概括到其他物质。调查小组包括来自哥伦比亚大学、密歇根大学的专家，以及一名兰德/NBER关于MML的专家，建立在现有合作的基础上。Nida PA 11-230鼓励对MML的研究。这项研究的信息将在科学上令人兴奋，并具有巨大的公共卫生意义。

DESCRIPTION (provided by applicant): Since 1996, 16 states have passed laws legalizing medical use of marijuana, and other states are considering such laws. With little scientific evidence available on whether these fast-changing laws lead to increased illicit adolescent marijuana use (AMU), the issue is now largely a matter of debate. Recently, using data from two national surveys, we showed that states with medical marijuana laws (MML) had significantly higher prevalence of adolescent (Wall et al., 2011) and adult marijuana use (Cerda et al., in press) than other states. The results underscore the importance of further research on MML and AMU, but they do not resolve the debate~ doing so requires explaining the higher AMU we found in states with MML. We propose to investigate four alternative explanations: (a) passage of MML directly increases AMU~ (b) passage of MML indirectly increases AMU, mediated by more favorable attitudes and/or increased availability~ (c) MML and AMU are associated because higher use and more favorable attitudes already characterize states that pass MML~ or (d) a reciprocal process exists, such that states with higher use and more favorable attitudes pass MML, which then further increase the risk for AMU. We will conduct the study using time series data from >1,000,000 adolescents collected annually since 1991 in the Monitoring the Future (MTF) survey. Due to the careful consistency in methods (e.g., procedures, questionnaires) across the years, MTF is the largest dataset available with relevant information on MML and AMU, including potential mediators of key interest, including attitudes related to marijuana (e.g., disapproval~ perceived risk), and perceived marijuana availability. Throughout the study, new data will be added on changes in state MML, and from the additional ~47,000 students surveyed yearly in the MTF. Data will be analyzed using state-of-the-art statistical methods (multilevel regression modeling with poststratification). We will examine yearly state MML and AMU, testing within-state trends relative to national trends, and explore varying time lags. Analyses will incorporate individual-level adolescent attitudes and perceived availability as potential mediators, and variables defined at the state level (e.g., population attitudes towards marijuana, state demographic composition, marijuana arrest rates) from Census and other data sources as potential determinants of MML passage. Further, we will explore whether variations in state MML (e.g., what the laws permit) influence the results, whether gender, SES and race/ethnicity moderate the relationship between MML and AMU, and whether relationships are specific to marijuana or generalize to other substances. The investigative team includes experts from Columbia University, University of Michigan, and a RAND/NBER expert on MML, building on pre-existing collaborations. NIDA PA 11-230 encourages research on MML. Information from the study will be scientifically exciting and have enormous public health significance.