Z-Drugs and their use in drug-facilitated crimes: a review of the literature

Background: Z-Drugs are a category of non-benzodiazepine sedative-hypnotic drugs that include Zolpidem, Zopiclone and Zaleplon. They are all rapidly adsorbed and have a very short half- life, features that make them first-line treatment of insomnia and, in the meantime, first-choice drugs in cases of poisoning for criminal purposes. Z-drugs are frequently use in Drug Facilitated Crime cases (DFC) and Drug Facilitated Sexual Assault (DFSA), namely crimes, robberies, extortion and sexual violence committed after administration of incapacitating substances able to induce sedative-hypnotic effects. In these circumstances, the psychoactive substance is considered as a weapon and constitutes an aggravating circumstance in the criminal act: accordingly, judicial authority legitimates the analytical determination of these substances. Currently, few tests able to detect such drugs are available in daily clinical practice. Aim: The aim of this work is to evaluate the effective utilization of Z-Drugs. Methods: We have analyzed the literature, focusing on cases in which the criminal use of such incapacitating substances has been demonstrated. Relevant scientific articles were identified from PubMed, Cochrane Central, Scopus, Web of Science, Science Direct, EMBASE up to December 2022 using the following keywords: "z-drugs", "drug facilitated crime", "forensic toxicology". The resulting references were screened to exclude duplicates. In addition, non-English papers were excluded. This evaluation left 10 articles (8 case reports and 2 original studies) divided as follows: 1 case report of a DFC (robbery), 6 cases of confirmed DFSA, 3 cases of suspected DFSA, 2 original studies about DFC. Results: The totality of the selected cases showed positive toxicological tests for a single intake of z-drugs. Conclusions: This work has shown the limitations of screening tests currently in use in the emergency rooms. Forensic toxicology tests should be introduced in daily clinical practice.