One-third of individuals with schizophrenia have treatment-resistant illness. Of these, up to 60% will respond to clozapine treatment.This study retrospectively examined clozapine prescribing patterns against National Institute for Health and Care Excellence (NICE) guidelines as treatment-resistant illness emerged in a first-episode psychosis cohort.A total of 339 individuals with a first-episode psychosis were included in the study. Clozapine prescribing patterns were compared against the NICE guidelines and the impact of clozapine use on one index of service utilisation (hospitalisation) was assessed.A total of 32 individuals (9.4%) from the cohort were prescribed clozapine. The mean time to clozapine trial was 2.1 years (SD 1.95; range 0.17-6.25). The mean number of adequate trials of antipsychotic prior to starting clozapine was 2.74 (SD 1.13; range 1-5). Following clozapine initiation, mean hospital admissions per year reduced from 2.3 to 0.3 (=0.00). Mean hospital days pre- and post-clozapine also reduced (147 . 53; =0.00). In total, 18 patients discontinued clozapine use during follow-up - 5 temporarily and 13 permanently.Patients are being prescribed clozapine earlier than previously demonstrated, though delays are still evident, and many patients discontinue treatment. More work needs to be undertaken to understand and address factors which lead to its discontinuation.