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

BACKGROUNDS 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. METHODS 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. RESULTS 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. CONCLUSION 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.