Abuse of Synthetic Cannabinoids in Forensic Psychiatric Hospitals

Background: Synthetic cannabinoids (SC) are a subgroup of "new psychoactive substances" (NPS) with particular importance due to both the number of substances available on the market and their prevalence in Germany. SC are consumed as an alternative to THC-containing cannabis, however SC have a less favourable risk profile compared to cannabis. Additionally, immunoassays tailored for cannabis cannot detect SCs and immunoassays specifically tailored towards SC have proven ineffective due to the dynamic nature of the SC market. This poses a large problem for effective abstinence control programs, especially in prisons and forensic-psychiatric clinics. Aim: The aim of this project was the investigation of SC prevalence in urine samples from forensic-psychiatric clinics. Methods: Urine samples sent to the Institute of Legal Medicine Freiburg by German forensic-psychiatric clinics between the beginning of 2018 and November 2023 were included. The samples were analysed for SC by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Results: Overall, a reduction of urine samples positive for SC from approx. 16 % in 2018 to approx. 10 % in 2023 was observed. However, in selected federal states, positivity rates showed deviating trends over the observed period, ranging from a very strong decrease of SC positivity rate to a twofold increase. Conclusion: Despite a general reduction of the SC positivity rate in urine samples over the observed period, the consumption of SC remains a relevant problem for abstinence control in psychiatric clinics. The results showed considerable differences in the different regions.