Objectives: The study assessed the presence of new psychoactive substances (NPS) in comparison to “classic” drugs in the group of newly admitted patients with mental and behavioral disorders due to the use of psychoactive substances diagnosis (section F11–19 according to ICD-10). Material and Methods: Data from anamnesis and the blood and urine samples were collected from 116 patients diagnosed with mental and behavioral disorders due to psychoactive substance use. All of them expressed written informed consent. Analytical confirmation was obtained by highperformance liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS). Liquid-liquid extraction was used for sample preparation. Results: In the sample, 108 (93%) of 116 were positive for psychoactive substances (including 96 cases where >1 substance was found), 69% of individuals were tested positive for opioids and 67% for benzodiazepines. Eleven (9%) of 116 patient samples were positive for NPS. We detected 7 different substances. Six of them were synthetic cannabinoids: PB-22, MDMB-CHMICA, MMB-CHMICA, AB-CHMINACA, MMB-FUBINACA, THJ-2201 and one synthetic cathinone 3-CMC. Conclusions: The prevalence and NPS profile (the predominance of synthetic cannabinoids) are similar in the group of people with addiction to psychoactive substances as in populations of people taking recreational drugs and the overdose patients admitted to the hospital. Int J Occup Med Environ Health. 2022;35(4):485–95