New Psychoactive Substances: transnational project on different user groups, user characteristics, extent and patterns of use, market dynamics, and best practices in prevention. This transnational project directly addresses priority area ‘New psychoactive substances’, i.e. ‘to support the implementation of EU legislation on new psychoactive substances by monitoring the extent and patterns of use of such substances, and by sharing best practices on prevention’. The proposed project is directly linked to the European Drugs Strategy 2013-2020. The main objectives are: 1. To determine the extent and patterns of NPS use within three different groups 2. Assess characteristics in three different groups of NPS users 3. Collect information about supply 4. Identify market dynamics for NPS 5. Assess perceptions of legal status of NPS 6. Make an inventory of prevention strategies used in the different countries 7. Identify best practices 8. Disseminate and share project results Europe-wide. The research took place in six EU Member States: Germany, Hungary, Ireland, the Netherlands, Poland and Portugal.