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This page is an AI-assisted Turkish summary of the study presented at the 26th World Congress of Psychiatry. The study belongs to the presenting authors; please refer to the original source when citing it.

The transdiagnostic effectiveness of clozapine

The trans-diagnostic effectiveness of clozapine

In national registry data from two countries, clozapine reduced the risk of psychiatric hospitalization across all diagnoses examined except borderline personality disorder, supporting its transdiagnostic effectiveness beyond treatment-resistant schizophrenia.

The study aimed to evaluate the effectiveness and safety of clozapine in psychiatric disorders other than treatment-resistant schizophrenia, where limited evidence has left these insufficiently established. This cohort study, conducted using nationwide registry data from Finland and Sweden, compared clozapine with other oral antipsychotics. It examined schizophrenia, schizoaffective disorder, delusional disorder, bipolar disorder, psychotic depression, major depressive disorder requiring inpatient treatment, and borderline personality disorder (BPD), using a within-individual design in which each patient served as their own control. The study population comprised 505,474 individuals, of whom 19,910 had used clozapine. Over a mean follow-up ranging from approximately 6 to 14 years depending on the cohort, clozapine use was associated with a reduced risk of psychiatric hospitalization for any reason, the primary outcome. This reduction was observed in all disorders except borderline personality disorder, with the largest reductions seen in schizophrenia and schizoaffective disorder, followed by delusional disorder, major depressive disorder, psychotic depression, and bipolar disorder. There was no evidence of an increased risk of all-cause hospitalization or mortality with clozapine in any disorder. In most disorders other than borderline personality disorder and psychotic depression, all-cause medication discontinuation rates were lower during clozapine treatment than during olanzapine treatment. In bipolar disorder, clozapine was also superior to mood stabilizers for the primary outcome. These findings, which were consistent across two independent national cohorts, support the transdiagnostic effectiveness and safety of clozapine, particularly in bipolar disorder and severe depressive conditions, and suggest that guidelines should reassess its role in these underrecognized indications. Evidence of benefit in borderline personality disorder, however, remains limited.

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