What’s so 'new’ about new psychoactive substances? Definitions, prevalence, motivations, user groups and a proposed new taxonomy.

This chapter provides an overview of the varied definitions of New Psychoactive Substances (NPS) or so-called ‘legal highs’, along with data on (relatively low) prevalence in selected countries and user motivations in order to tease out the broader picture of what characterises NPS use. A new typology of NPS is proposed which couples pharmacological effects with chemical classifications, to provide an underlying framework for this review. The authors conclude that the dynamic interaction between the NPS market and policy change initially characterised as ‘cat and mouse’ might now be conceived of as ‘hare and hounds’ in that legislative control has been a significant driving force in manufacturing and retail innovation