Reducing youth cannabis use in Canada is a public health priority with schools of interest as a potential modifier of behavior and as a venue for prevention programming. This work aimed to provide a basis for future policy and programming by evaluating pre-legalization cannabis use change patterns in schools and the impact of school characteristics on these patterns. Average rates of cannabis use behavior change (initiation, escalation, reduction, cessation) were collected from 88 high schools located in Ontario and Alberta, Canada participating in the COMPASS prospective cohort study. There was little variability in cannabis use behaviors between schools with intra-class correlation coefficients lowest for cessation (0.02) and escalation (0.02) followed by initiation (0.03) and reduction (0.05). Modest differences were found based on school province, urbanicity and student-peer use. Cannabis ease of access rates had no significant effect. Fewer than half the schools reported offering school drug use prevention programs; these were not significantly associated with student cannabis use behaviors. In conclusion, current school-based cannabis prevention efforts do not appear sufficiently effective. Comprehensive implementation of universal prevention programs may reduce cannabis harms. Some factors (urbanicity, peer use rates) may indicate which schools to prioritize.

中文翻译：

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学校特征在合法化前的大麻使用中的作用在加拿大青年中发生变化：对政策和减少危害的影响。

在加拿大，减少青年大麻的使用是公共卫生的优先事项，感兴趣的学校可以作为行为的潜在调节器和预防方案的场所。这项工作旨在通过评估合法化前大麻在学校中的使用变化模式以及学校特征对这些模式的影响，为未来的政策和规划提供基础。大麻的平均使用行为变化率（启动，升级，减少，戒烟）来自加拿大安大略省和艾伯塔省的88所高中，参加了COMPASS前瞻性队列研究。班级间相关系数最低的学校之间的大麻使用行为几乎没有变化，其中停止（0.02）和升级（0.02），继发（0.03）和减少（0.05）最低。根据学校所在省份，城市化程度和学生同龄人的使用情况，发现差异很小。大麻的普及率没有显着影响。不到一半的学校报告提供了预防学校毒品使用计划；这些与学生大麻使用行为没有显着相关。总之，目前基于学校的大麻预防工作似乎还不够有效。全面实施普遍预防方案可减少大麻危害。某些因素（城市性，同龄人使用率）可能表明要优先考虑的学校。当前基于学校的大麻预防工作似乎没有足够的效果。全面实施普遍预防方案可减少大麻危害。某些因素（城市性，同龄人使用率）可能表明要优先考虑的学校。当前基于学校的大麻预防工作似乎没有足够的效果。全面实施普遍预防方案可减少大麻危害。某些因素（城市性，同龄人使用率）可能表明要优先考虑的学校。