Case ReportsOne Plus One Sometimes Equals More Than Two: Long-acting Injectable Aripiprazole Adjunction in Clozapine-Resistant SchizophreniaBalcioglu, Yasin Hasan MD∗; Gokcay, Hasan MD†; Yesilkaya, Umit Haluk MD∗ Author Information ∗Department of Psychiatry, Bakirkoy Prof Mazhar Osman Training and Research Hospital for Psychiatry, Neurology, and Neurosurgery †Department of Psychiatry, University of Health Sciences, Bagcilar Training and Research Hospital, Istanbul, Turkey. Address correspondence and reprint requests to Yasin Hasan Balcioglu, MD, Department of Psychiatry, Bakirkoy Prof Mazhar Osman Training and Research Hospital for Psychiatry, Neurology, and Neurosurgery, 34147, Istanbul, Turkey; E-mail: [email protected] Conflicts of Interest and Source of Funding: The authors have no conflicts of interest to declare. Informed consents were obtained from the patient and his legal representative after explaining why we requested their permission to use their clinical information in scientific work. Clinical Neuropharmacology 43(5):p 166-168, 9/10 2020. | DOI: 10.1097/WNF.0000000000000404 Buy Metrics Abstract In this report, we present a patient whose positive symptoms did not improve despite being treated with clozapine monotherapy at a therapeutic dose for 4 months, and whose symptoms began to resolve after aripiprazole long-acting injection adjunction to clozapine. A 22-year-old man was diagnosed as having schizophrenia last year in his first admission, with symptoms of auditory hallucinations, persecutory delusions, and associated social withdrawal. His positive symptoms did not improve despite being treated with risperidone, olanzapine, and paliperidone. Oral clozapine monotherapy was planned, and the daily dose was increased to provide a therapeutic plasma clozapine concentration and measured as effective (545 mg/dL). Aripiprazole long-acting injection 400 mg monthly was combined with the ongoing clozapine treatment for augmentation. One week after the third injection, a psychiatric examination revealed a significant improvement in the positive symptoms, and his caregivers confirmed an increase in the social interaction of the patient. Although we cannot postulate on a single exact mechanism for the increased efficacy of clozapine and aripiprazole combination, we may suggest that, at least for a subgroup of patients with schizophrenia who respond clinically to clozapine at a suboptimal level, combination with aripiprazole may be an effective therapeutic strategy. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.