Real-world effectiveness of antipsychotic monotherapy and polytherapy in 1543 patients with acute-phase schizophrenia.

•In total, there were 660 (42.8%) and 243 (15.7%) responders to an initial and a second antipsychotic, respectively; thus, 58.5% of all patients were responders to an initial or second antipsychotic in the real-world acute-phase treatment for schizophrenia.•Among 581 nonresponders (37.7%), the initial antipsychotic or a third antipsychotic was added to the second antipsychotic. Among these patients, 89.8% showed a Clinical Global Impression-Improvement score ≤3 (from ‘minimally improved’ to ‘very much improved’).•The rates of adverse events such as hyperglycemia, hyper-low-density lipoprotein cholesterolemia, hypertriglyceridemia, hyperprolactinemia, QTc prolongation, and extrapyramidal symptoms were not high in patients receiving augmentation with two antipsychotics compared with all patients, and no serious adverse events were reported.