Introduction: In the last twenty years we have seen a change in the drug abuse market. New ways of producing, selling, buying and consuming as well as the advent of some web sites have facilitated the emergence and spread of ‘new psychoactive substances’ (NSP). At the same time, the market for “traditional” drugs was implemented – too if not completely replaced – by a remarkable variety of new compounds with psychoactive properties. Materials and methods: A computerized research was carried out for the articles to be inserted through use of international databases such as pubmed, scopus, researchgate, google scholar, by typing in keywords such as NPS together with the various classes of substances considered (cathinones, piperazines and fentanyl-likes compounds) followed by some names of compounds belonging to the single categories, integrated with literature data. Also they are data from paper documents such as books and articles have been added. Discussion and conclusions: Over a thousand new psychoactive substances (NPS) have been analyzed in recent years as the cause of acute intoxication among patients, often young, belonging to the emergency departments for especially acute psychiatric patients. Among the various NPS in this article, three of the most common classes have been analyzed, namely cathinones, piperazines and opioid derivatives of fentanyl.We focused on the chemical characteristics of the molecules and on the structure-activity relationship, or on their cellular toxicology on the central nervous system, explaining the mechanisms of action, bearing in mind that for these substances, the long-term toxicity mechanisms are still unknown. given that often patients come to observation only to stop episodes of acute intoxication and there are no specific treatments for their cessation, even if some (for example fentanyl) have properties of abuse and euphoria.
Keywords: Addiction. NPS. New- psychoactive. Xenobiotics.