Clozapine and Treatment-Resistant Schizophrenia: Prescribing Patterns at a Neuropsychiatric Hospital in the City of Buenos Aires

Abstract

Objective: Despite being a highly effective drug for treatment-resistant schizophrenia (TRS), clozapine remains underutilized. This study aims to evaluate clozapine prescribing patterns in outpatients from a specialized psychiatric hospital in Argentina. Methods: This retrospective, observational, cross-sectional study included adult patients with a diagnosis of schizophrenia receiving outpatient treatment at our institution. Data were collected by reviewing medical records from November 2024 to January 2025. Statistical analyses included descriptive statistics, paired t-tests, Pearson's correlations, and multiple regression. Results: The sample included 199 patients with a mean age of 36 years (SD: 6.6). A total of 75.4% were receiving concomitant medication; prior use of long-acting injectable antipsychotics (LAIs) was low (8%), while antipsychotic polypharmacy was frequent (30.6%). The mean time from schizophrenia diagnosis to clozapine initiation was greater than five years (266.47 weeks, SD: 270.4), with a mean of 3.17 adequate prior antipsychotic trials (SD: 1.53). Hospitalizations significantly decreased after clozapine initiation (mean change: 1.74, SD: 1.14; large effect size, d = 1.09). Conclusions: Our findings indicate that clozapine continues to be underutilized in our setting and highlight the importance of earlier initiation to reduce hospitalization rates and improve clinical outcomes.