Discussion and the future

This paper clarifies NPS and reviews the origin and drivers of the phenomenon. We summarise recent evidence on NPS availability and present a systematic review of literature that attempts to quantify the scale of use and harms, and the sociodemographic and risk characteristics of people who use NPS. Finally, we discuss challenges of, and responses to, the NPS phenomenon from various perspectives, including drug control, monitoring and surveillance, and evidence-based policy.