Objectives: Assess the impact of selective prohibition and seizure of 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 1st October 2015 – 31st March 2016. Setting: General Psychiatry inpatients and Intensive Home Treatment Team community patients at a psychiatric hospital in a Scottish city. Participants: All participants were between the ages 18-65. After application of exclusion criteria, 473 discharge letters of General Psychiatry patients were deemed suitable for analysis and 264 Intensive Home Treatment Team (IHTT) patient discharge letters were analysed. Interventions: A nationwide Temporary Class Drug Order (TCDO) was placed on 10th April 2015 reclassifying methylphenidate-related compounds as Class B substances. On 15th 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. Secondly, 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 to non-users were more likely to be male (OR: 2.92, 95% CI: 1.28-6.66, p=0.009), have a forensic history (OR: 5.03, CI: 2.39-10.59, p<0.001) and be detained under an Emergency Detention Certificate (OR: 3.50, CI: 1.56-7.82, p=0.004). NPS users were also more likely to be diagnosed under ICD-10 F10-19 (OR: 9.97, CI: 4.62-21.49, p<0.001). Conclusions: Compared to 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.