New psychoactive substances and suicidality: A systematic review of the current literature

Background and Objectives: Over the past twenty years a large number of new psychoactive substances (NPS) have entered and modified the recreational drug scene. Their intake has been associated with health-related risks, especially so for vulnerable populations such as people with severe mental illness, who might be at higher risk of suicidality or self-injurious behavior. This paper aims at providing an overview of NPS abuse and the effects on mental health and suicidality issues, by performing a literature review of the current related knowledge, thereby identifying those substances that, more than others, are linked to suicidal behaviors. Materials and Methods: A comprehensive and updated overview of the literature regarding suicidality and NPS categories has been undertaken. An electronic search was performed, including all papers published up to March 2021, using the following keywords "NPS" OR "new psychoactive substances" OR "novel psychoactive substances" OR "synthetic cannabinoids" OR "phenethylamines" OR "synthetic cathinones" OR "tryptamines" OR "piperazines" OR "new synthetic opioids" OR "designer benzodiazepines" AND ("suicide" OR "suicidality") NOT review NOT animal on the PubMed, Cochrane Library, and Web of Science online databases. Results: Suicidality and self-injurious behavior appear to be frequently associated with some NPS such as cathinones, synthetic cannabinoids, and new synthetic opioids. The results are organized according to the substances recorded. Conclusion: The growing use of NPS has become a significant clinical issue, causing increasing concern and challenges for clinicians working in both mental health and emergency departments. Thus, considering the associations between NPS and suicidality or self-injurious behaviors, areas where suicide-prevention efforts and strategies might be focused are the early detection, monitoring, and restriction of NPS.