An overview of emerging and new psychoactive substances in the United Kingdom.

The purpose of this review is to identify emerging or new psychoactive substances (NPS) by undertaking an online survey of the UK NPS market and to gather any data from online drug forums and published literature. Drugs from four main classes of NPS were identified: psychostimulants, dissociative anaesthetics, hallucinogens (phenylalkylamine-based and lysergamide-based materials) and finally benzodiazepines. For inclusion in the review, the 'user reviewers' on drugs forums were selected based on whether or not the particular NPS of interest was used alone or in combination. NPS that were used alone were considered. Each of the classes contained drugs that are modelled on existing illegal materials and will be covered by the UK New Psychoactive Substances Bill in 2016.