Non-medical use of prescription opioids and prescription opioid-related harms: why so markedly higher in North America compared to the rest of the world?

Aims: This paper aims to identify possible system-level factors contributing to the marked differences in the levels of non-medical prescription opioid use (NMPOU) and prescription opioid (PO)-related harms in North America (i.e. the United States and Canada) compared to other global regions.