Effectiveness of Clozapine on Employment Outcomes in Treatment-Resistant Schizophrenia: A Retrospective Bidirectional Mirror-Image Study

Purpose: Clozapine is more effective than other antipsychotics and is the only antipsychotic approved for treatment-resistant schizophrenia. The objective of this study is to reveal the effect of clozapine on employment using a bidirectional mirror-image model. Patients and Methods: This design was a retrospective observational study that investigated the employment status of patients with treatment-resistant schizophrenia based on medical records. The bidirectional mirror-image model consisted of 1) switching from other antipsychotics to clozapine and 2) switching from clozapine to other antipsychotics. The observation period was 1 year for each pre-and post-clozapine initiation and discontinuation. Results: We included 36 patients in the bidirectional mirror-image model. The regular employment plus employment support rate was significantly higher in the clozapine phase than in the other antipsychotic phase in the bidirectional mirror-image model (30.6% vs 11.1%, P = 0.039). The days of regular employment plus employment support were also significantly longer in the clozapine phase (61.3 ± 106.2 vs 24.7 ± 82.7 days, P = 0.032). As per the unidirectional mirror-image model, switching to clozapine resulted in significantly higher regular employment plus employment support rates in the clozapine phase than those in the other antipsychotic phase (33.3% vs 10.0%, P = 0.039). Switching from clozapine to other antipsychotics did not exhibit significant differences in any outcomes. Conclusion: The results suggest that clozapine is superior to other antipsychotics with respect to achieving employment in patients with treatment-resistant schizophrenia. However, biases specific to the mirror-image model need to be considered.