Prevalence and Surveillance of Synthetic Cathinones Use by Hair Analysis: An Update Review.

New psychoactive substances (NPS) have emerged in a threatening way in the last decades. They are sold via the internet or head shops with several names (bath salts, Research chemical, RCs, Legal Highs) and forms (pills, tablets, powder...etc.), and are labelled ambiguously to escape governmental legislation. Designer drugs belong to different chemical classes, but cathinones derivatives presented the most prevalent group. In 2013, this group accounted for 30% of NPS seizures in Europe with more than 450 different compounds, including 101 new molecules reported for the first time in 2014. The increased number of NPS as being sold in parallel market has led several countries to adopt different strategies either on individual surveillance of new emerging drugs or more efficiently on generic control regrouping a wide number of isomers and structurally similar compounds. The identification of these substances is a challenge for toxicologists, which requires sensitive and specific analytical methods based on LC-MS/MS or GC-MS. The usefulness of hair as an alternative matrix for prevalence studies was proved since it offers an overview on drug exposure with a large detection window over weeks or even months and years according to the length of the hair strand. However, as for many drugs of abuse, prevalence studies on cathinones derivatives use are still scarce. Self-reported use or case reports provide most of the available data. The aim of this paper is to provide an update review on prevalence and surveillance of synthetic cathinones use conducted by hair analysis, excluding case report.