The Emergence of New Psychoactive Substance (NPS) Benzodiazepines. A Survey of their Prevalence in Opioid Substitution Patients using LC-MS Posted by IMJ on August 1, 2019 The-Emergence-of-New-Psychoactive-Substance-NPS-Benzodiazepines.-A-Survey-of-their-Prevalence-in-Opioid-Substitution-Patients-using-LC-MS