Long-term sustained benefits of clozapine treatment in refractory early onset schizophrenia: A retrospective study in Korean children and adolescents

Objective: Treatment resistance in early onset schizophrenia (EOS) is one of the most challenging problems in child and adolescent psychiatry. We retrospectively examined the therapeutic dosage, clinical response, and side effect profiles of long‐term clozapine treatment in Korean children and adolescents with refractory EOS or very early onset schizophrenia (VEOS). Method: 26 refractory patients treated with clozapine for more than 1 year were analyzed. Efficacy was determined by comparing hospitalization rate and duration, before and after clozapine treatment. Tolerability was assessed through review of documented adverse events. Results: A significant reduction in hospital days per year was observed in 25 (96.2%) patients after clozapine treatment compared to before clozapine. Long‐term benefit of the treatment was supported by a further reduction of the hospitalization rate in 14 patients treated with clozapine for more than 3 years. Neutropenia developed in 26.9% patients at 1 year and there was no agranulocytosis. Overall, eight male patients (8/12, 66.7%) and one female patient (1/14, 7%) developed neutropenia and out of the nine patients, seven patients were maintained and two patients were successfully rechallenged on clozapine. Conclusion: These findings suggest that long‐term clozapine treatment may effectively reduce the amount of time Asian patients with refractory EOS or VEOS spend in the hospital. However careful monitoring of adverse events is required. Copyright © 2008 John Wiley & Sons, Ltd.