Characteristics of NPS use in patients admitted to acute psychiatric services in Southeast Scotland: a retrospective cross-sectional analysis following public health interventions

OBJECTIVES: Assess the impact of selective prohibition and seizure of novel psychoactive substances (NPS) supply on NPS use prevalence within psychiatric admissions and evaluate demographic characteristics of current NPS users. DESIGN: A 6-month retrospective cross-sectional analysis of discharge letters between 1 October 2015 and 31 March 2016. SETTING: General psychiatry inpatients and intensive home treatment team (IHTT) community patients at a psychiatric hospital in a Scottish city. PARTICIPANTS: All participants were between the ages of 18 and 65 years. After application of exclusion criteria, 473 discharge letters of general psychiatry patients were deemed suitable for analysis and 264 IHTT patient discharge letters were analysed. INTERVENTIONS: A nationwide temporary class drug order (TCDO) was placed on 10 April 2015 reclassifying methylphenidate-related compounds as class B substances. On 15 October 2015, local forfeiture orders were granted to trading standards permitting the seizure of NPS supplies. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome measure was to determine the prevalence of NPS use in two cohorts. Second, demographic features of patients and details regarding their psychiatric presentation were analysed. RESULTS: The prevalence of NPS use in general psychiatry and IHTT patients was 6.6% and 3.4%, respectively. Inpatients using NPS compared with non-users were more likely to be men (OR 2.92, 95% CI 1.28 to 6.66, P=0.009), have a forensic history (OR 5.03, CI 2.39 to 10.59, P<0.001) and be detained under an Emergency Detention Certificate (OR 3.50, CI 1.56 to 7.82, P=0.004). NPS users were also more likely to be diagnosed under International Statistical Classification of Diseases and Related Health Problems, Version 10, F10–19 (OR 9.97, CI 4.62 to 21.49, P<0.001). CONCLUSIONS: Compared with previous work, psychiatric inpatient NPS use has fallen. NPS continue to be used by a demographic previously described resulting in presentations consistent with a drug-induced psychosis and at times requiring detention under the Mental Health Act. Further research is required to evaluate the effectiveness of the recent prohibition of all NPS.