The effects and risks associated to mephedrone and methylone in humans: A review of the preliminary evidences

New psychoactive substances have drastically modified the world drug scene. An increasingly popular class comprises synthetic or substituted cathinones (legal highs, research chemicals, bath salts). Among the most common psychoactive constituents of bath salts are mephedrone and methylone. Recent reports on the abuse of novel synthetic cathinone derivatives call attention to the serious physical and psychological risks resulting from their consumption, thereby emphasizing the growing use of these drugs might constitute an important public health issue. In this paper, we will review the available data regarding the use and effects of mephedrone and methylone in humans in order to highlight their impact on public health. To reach this objective, a literature search was performed on two representative databases (Pubmed, Google Scholar), the Erowid Center website (a US non-profit educational organization that provides information about psychoactive plants and chemicals), and various governmental websites. The terms used for the database search were “mephedrone”, “methylone”, “new psychoactive substances”, “synthetic cathinones”, “substituted cathinones”, “substance abuse”, “substance use disorder”, “adverse effects”, “fatalities”. The literature search was limited to years 2005–2015 and led to the identification of 71 potentially relevant articles. To date, the actual prevalence rates of their use remains difficult to estimate. Important health-related issues have emerged in relation to the somatic, psychiatric, and addictive consequences of their use. The potential chronic health effects of their prolonged use remain to date unknown (e.g., reproductive toxicity, genotoxicity and carcinogenic potential). Treatment for patients with prolonged exposure to synthetic cathinones should ideally include a drug management plan coupled with psychotherapy taking place in a structured program of care.