This report presents the findings from the seventeenth year in which data has been collected in South Australia (SA). The Ecstasy and Related Drugs Reporting System (EDRS) monitors the price, purity and availability of ‘ecstasy’ (MDMA) and other drugs such as methamphetamine, cocaine, gamma-hydroxybutyrate (GHB), ketamine, d-lysergic acid (LSD), and 3,4-methylendioxyamphetamine (MDA). It also examines the demographic characteristics and patterns of drug use among regular psychostimulant users (RPU), the prevalence of risk-taking and harms related to drug use, as well as the level of criminal involvement among this group. It utilises data from three sources: (a) surveys with RPU; (b) surveys with key experts (KE) who have contact with RPU through the nature of their work; and (c) the analysis of existing data sources that contain information on ecstasy and related drugs (ERD). The EDRS surveys are not representative of psychostimulant users in the general population. The RPU are a sentinel group that provides information on patterns of drug use and market trends.