Unexpected resolution of clozapine-induced obsessive-compulsive symptoms with cariprazine augmentation: a case report.

INTRODUCTION: The management of obsessive–compulsive symptoms (OCS) in patients with schizophrenia is challenging, as many antipsychotics can induce OCS. Increasing evidence supports the use of partial agonists in managing these cases. This case report describes a patient with treatment-resistant schizophrenia and clozapine-induced obsessive–compulsive symptoms who underwent multiple antipsychotic regimens without significant improvement. THE PATIENT’S MAIN CONCERNS AND IMPORTANT CLINICAL FINDINGS: The patient's symptoms progressed gradually, and their condition was managed entirely on an outpatient basis. Despite multiple adjustments to antipsychotic medications (risperidone, then haloperidol, then aripiprazole), the patient showed only a partial response to treatment, leading to their classification as treatment-resistant. THE PRIMARY DIAGNOSES, INTERVENTIONS, AND OUTCOMES: Due to the lack of adequate response, the medical team decided to prescribe clozapine. However, at a dose of 350 mg, clozapine triggered compulsive checking and washing behaviors. Consequently, the team initiated treatment with a third-generation antipsychotic, cariprazine, at a dose of 6 mg, combined with sertraline at 100 mg while gradually reducing clozapine. Unexpectedly, there was a significant improvement in both psychotic symptoms and OCS. CONCLUSION: The combination of cariprazine, as a D3 partial agonist, with clozapine may be an effective approach for managing challenging cases of treatment-resistant schizophrenia associated with de novo OCS.