"The NPS phenomenon remains a considerable challenge due to its evolving nature. The range of compounds currently on the drug market is constantly changing, with new and previously unknown substances entering the market every year. Despite the implementation of regulatory countermeasures and the development of extensive early warning systems and their adaptation to the current situation, NPS including synthetic cathinones are still available and widespread [78, 79]. One of the potential reasons for the continuous phenomenon of NPS is the lack of international consensus on the legal control of these drugs despite the existence of a common basis for UN member countries, namely the three International Drug Control Conventions: the 1961 United Nations Single Convention on Narcotic Drugs, the 1971 United Nations Convention on Psychotropic Substances, and the 1988 United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances. Different legislative approaches in each country affect local drug market appearance and control, and may contribute to different dynamics of developing NPS situations in different regions of the world [80, 81]. Some countries base their drug policy on individual listing, some on generic legislation or analog control, and in many countries there is a hybrid system drawing on solutions from different legislative approaches [81,82,83,84]. In 2013, the UNODC established an Early Warning Advisory (EWA) as a response at the global level to the increasing prevalence of NPS [85]. Since its launch in 2013 until the beginning of 2022, a total of 136 countries had reported a total of over 1100 individual substances [86]. Furthermore, at the European level, EMCDDA had monitored around 830 NPS at the end of 2020, 46 of which had been detected for the first time in Europe in 2020 [87]. In recent years, the number of substances reported in Europe has remained more or less constant at 400 compounds each year. In 2019, synthetic cathinones (156 compounds) were the second most numerous group after synthetic cannabinoids (209 compounds); these categories accounted for almost 60% of the number of seizures in EU Member States [87]."

Source

Kuropka, P., Zawadzki, M. & Szpot, P. A review of synthetic cathinones emerging in recent years (2019–2022). Forensic Toxicol 41, 25–46 (2023). doi.org/10.1007/s11419-022-00639-5.