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，有16个州通过了大麻医用合法化的法律，其他州正在考虑制定此类法律。关于这些快速变化的法律是否导致青少年非法使用大麻（AMU）的增加，几乎没有科学证据，这个问题现在很大程度上是一个争论的问题。最近，利用两项全国调查的数据，我们发现，与其他州相比，拥有医用大麻法律（MML）的州，青少年（Wall et al., 2011）和成人使用大麻（Cerda et al., in press）的患病率明显更高。这些结果强调了进一步研究MML和AMU的重要性，但它们并没有解决争论——这样做需要解释我们在有MML的州发现的更高的AMU。我们建议调查四种不同的解释：(a) MML的传递直接增加了AMU~ (b) MML的传递通过更有利的态度和/或可用性的增加间接增加了AMU~ (c) MML和AMU是相关的，因为更高的使用和更有利的态度已经成为通过MML的国家的特征~或(d)存在一个相互作用的过程，使得更高使用和更有利的态度的国家通过MML，然后进一步增加AMU的风险。我们将使用自1991年以来在监测未来（MTF）调查中每年收集的1,000,000名青少年的时间序列数据进行研究。由于多年来方法（例如，程序，问卷）的仔细一致性，MTF是最大的可用数据集，其中包含MML和AMU的相关信息，包括关键利益的潜在中介，包括与大麻相关的态度（例如，不赞成~感知风险）和感知大麻可用性。在整个研究过程中，新的数据将被

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.