Effect of Clozapine vs Other Second-Generation Antipsychotics on Hospitalization and Seclusion: A Retrospective Mirror-Image Study in a Japanese Public Psychiatric Hospital.

BACKGROUND: Clozapine has been regarded as the gold standard for patients with treatment-resistant schizophrenia, but a recent network meta-analysis has questioned its relative superiority over other second-generation antipsychotics (SGAs) such as olanzapine and risperidone.

PURPOSE: We conducted a retrospective mirror-image study of clozapine vs other SGAs to evaluate real-world effectiveness of clozapine in terms of the duration of hospitalization and seclusion, both of which represent a critical outcome.

METHODS: We included all patients who initiated clozapine at the Yamanashi Prefectural KITA Hospital and had continued to take any SGA(s) other than clozapine for at least 1 year before the initiation of clozapine. We obtained data on hospitalization and seclusion during 1 year of SGA treatment (SGA phase) and 1 year after the treatment was switched to clozapine (clozapine phase).

RESULTS: The study included 35 patients (21 men, 31 with schizophrenia, 4 with schizoaffective disorder) with the average ± SD age of 37.3 ± 11.1 years. The results indicated that total hospitalization days did not differ significantly between SGA and clozapine treatment. However, total duration of seclusion was significantly shorter in the clozapine phase than in the SGA phase. Furthermore, the number of patients who were secluded at least once was significantly smaller in the clozapine phase than in the SGA phase. The results were essentially unchanged when outlier patients were excluded and only when patients taking olanzapine and/or risperidone during the SGA phase were considered.

CONCLUSIONS: Although the findings from this retrospective analysis need to be further tested in prospective trials, they endorse the relative effectiveness of clozapine over other SGAs in the real world.