Supplementary Material for: Explaining the Differences in Opioid Overdose Deaths between Scotland and England/Wales: Implications for European Opioid Policies

<b><i>Backgrounds:</i></b> Between 2009 and 2018, the number of opioid-related deaths (ORDs) in Scotland showed a dramatic increase, whereas in England and Wales, a much lower increase in ORD was seen. This regional difference is remarkable, and the situation in Scotland is worrisome. Therefore, it is important to identify the drivers of ORD in Scotland. <b><i>Methods:</i></b> A systematic literature review according to PRISMA guidelines was conducted to identify peer-reviewed studies about key drivers for the observed differences in ORDs between Scotland and England/Wales. In addition, non-peer-reviewed reports on nationwide statistical data were retrieved via Google and Google Scholar and analysed to quantify differences in ORD drivers between Scotland and England/Wales. <b><i>Results:</i></b> The systematic review identified some important drivers of ORD, but none of these studies provided direct or indirect comparisons of ORD drivers in Scotland and England/Wales. However, the reports with nationwide statistical data showed important differences in ORD drivers between Scotland and England/Wales, including a higher prevalence of people using opioids in a problematic way (PUOP), more polydrug use in people using drugs in a problematic way (PUDP), a higher age of PUDP, and lower treatment coverage and efficacy of PUDP in Scotland compared to England/Wales, but no regional differences in injecting drug use, incarceration/prison release without treatment, and social deprivation in PUDP. <b><i>Conclusion:</i></b> It is concluded that the opioid crisis in Scotland is best explained by a combination of drivers, consisting of a higher population involvement in (problematic) opioid use (notably methadone), relatively more polydrug use (notably benzodiazepines and gabapentinoids), a steeper ageing of the PUOP population in the past 2 decades, and lower treatment coverage and efficacy in Scotland compared to England/Wales. The findings have important consequences for strategies to handle the opioid crisis in Scotland.

**背景**：2009年至2018年间，苏格兰的阿片类药物相关死亡（opioid-related deaths, ORDs）数量呈大幅攀升态势，而英格兰与威尔士的阿片类药物相关死亡增幅则相对平缓。这一区域差异十分显著，苏格兰的相关形势令人担忧，因此明确苏格兰阿片类药物相关死亡的驱动因素至关重要。**研究方法**：本研究遵循PRISMA指南开展系统文献综述，旨在筛选探讨苏格兰与英格兰/威尔士两地阿片类药物相关死亡差异关键驱动因素的同行评议研究。此外，本研究通过谷歌（Google）及谷歌学术（Google Scholar）检索非同行评议的全国统计数据报告并展开分析，以量化两地阿片类药物相关死亡驱动因素的差异。**研究结果**：本系统综述识别出若干影响阿片类药物相关死亡的重要驱动因素，但尚无研究直接或间接对比苏格兰与英格兰/威尔士两地的阿片类药物相关死亡驱动因素。然而，全国统计数据报告显示，两地在阿片类药物相关死亡驱动因素上存在显著差异：苏格兰的问题性阿片类药物使用人群（people using opioids in a problematic way, PUOP）占比更高，问题性药物使用人群（people using drugs in a problematic way, PUDP）中多药滥用情况更为普遍，该人群平均年龄更大，且治疗覆盖率与治疗效果均低于英格兰/威尔士；但两地在注射吸毒、未接受治疗的监禁/刑满释放人员比例，以及问题性药物使用人群的社会剥夺程度上并无区域差异。**研究结论**：综上，苏格兰的阿片类药物危机可由以下多重驱动因素共同解释：相较于英格兰与威尔士，苏格兰存在更高比例的（问题性）阿片类药物使用人群（尤以美沙酮使用者为甚）、更为普遍的多药滥用情况（尤以苯二氮䓬类与加巴喷丁类药物为甚）、近二十年来问题性阿片类药物使用人群的老龄化趋势更为显著，以及更低的治疗覆盖率与治疗效果。本研究结果对苏格兰应对阿片类药物危机的相关策略具有重要参考价值。