Charlson FJ, Ferrari AJ, Santomauro DF, et al. Global epidemiology and burden of Schizophrenia: findings from the global burden of disease study 2016. Schizophr Bull. 2018;44(6):1195–203. https://doi.org/10.1093/schbul/sby058.

Article  PubMed  PubMed Central  Google Scholar 

Kahn RS, Sommer IE, Murray RM, et al. Schizophrenia. Nat Rev Dis Primer. 2015;2:15067. https://doi.org/10.1038/nrdp.2015.67.

Article  Google Scholar 

McCutcheon RA, Pillinger T, Efthimiou O, et al. Reappraising the variability of effects of antipsychotic medication in schizophrenia: a meta-analysis. World Psychiatry. 2022;21(2):287–94. https://doi.org/10.1002/wps.20977.

Article  PubMed  PubMed Central  Google Scholar 

Winkelbeiner S, Leucht S, Kane JM, Homan P. Evaluation of differences in individual treatment response in schizophrenia spectrum disorders: a meta-analysis. JAMA Psychiat. 2019;76(10):1063–73. https://doi.org/10.1001/jamapsychiatry.2019.1530.

Article  Google Scholar 

Sarpal DK, Argyelan M, Robinson DG, et al. Baseline striatal functional connectivity as a predictor of response to antipsychotic drug treatment. Am J Psychiatry. 2016;173(1):69–77. https://doi.org/10.1176/appi.ajp.2015.14121571.

Article  PubMed  Google Scholar 

Li A, Zalesky A, Yue W, et al. A neuroimaging biomarker for striatal dysfunction in schizophrenia. Nat Med. 2020;26(4):558–65. https://doi.org/10.1038/s41591-020-0793-8.

Article  CAS  PubMed  Google Scholar 

Samara MT, Leucht C, Leeflang MM, et al. Early improvement as a predictor of later response to antipsychotics in schizophrenia: a diagnostic test review. Am J Psychiatry. 2015;172(7):617–29. https://doi.org/10.1176/appi.ajp.2015.14101329.

Article  PubMed  Google Scholar 

Leucht S, Kane JM, Kissling W, Hamann J, Etschel E, Engel RR. What does the PANSS mean? Schizophr Res. 2005;79(2–3):231–8. https://doi.org/10.1016/j.schres.2005.04.008.

Article  PubMed  Google Scholar 

Remington G, Addington D, Honer W, Ismail Z, Raedler T, Teehan M. Guidelines for the pharmacotherapy of schizophrenia in adults. Can J Psychiatry. 2017;62(9):604–16. https://doi.org/10.1177/0706743717720448.

Article  PubMed  PubMed Central  Google Scholar 

Keepers GA, Fochtmann LJ, Anzia JM, et al. The American psychiatric association practice guideline for the treatment of patients with schizophrenia. Am J Psychiatry. 2020;177(9):868–72. https://doi.org/10.1176/appi.ajp.2020.177901.

Article  PubMed  Google Scholar 

Hasan A, Falkai P, Wobrock T, et al. World Federation of Societies of Biological Psychiatry (WFSBP) Guidelines for Biological Treatment of Schizophrenia, part 1: update 2012 on the acute treatment of schizophrenia and the management of treatment resistance. World J Biol Psychiatry. 2012;13(5):318–78. https://doi.org/10.3109/15622975.2012.696143.

Article  PubMed  Google Scholar 

Buckley PF, Correll CU. Strategies for dosing and switching antipsychotics for optimal clinical management. J Clin Psychiatry. 2008;69(Suppl 1):4–17.

PubMed  Google Scholar 

Kahn RS, van Winter RI, Leucht S, et al. Amisulpride and olanzapine followed by open-label treatment with clozapine in first-episode schizophrenia and schizophreniform disorder (OPTiMiSE): a three-phase switching study. Lancet Psychiatry. 2018;5(10):797–807. https://doi.org/10.1016/S2215-0366(18)30252-9.

Article  PubMed  Google Scholar 

Correll CU, Rubio JM, Inczedy-Farkas G, Birnbaum ML, Kane JM, Leucht S. Efficacy of 42 pharmacologic cotreatment strategies added to antipsychotic monotherapy in schizophrenia: systematic overview and quality appraisal of the meta-analytic evidence. JAMA Psychiat. 2017;74(7):675–84. https://doi.org/10.1001/jamapsychiatry.2017.0624.

Article  Google Scholar 

Galling B, Roldán A, Hagi K, Rietschel L, Walyzada F, Zheng W, et al. Antipsychotic augmentation vs monotherapy in schizophrenia: systematic review, meta-analysis and meta-regression analysis. World Psychiatry. 2017;16(1):77–89.

Article  PubMed  PubMed Central  Google Scholar 

Moher D, Liberati A, Tetzlaff J, Altman DG. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med. 2009;6(7): e1000097. https://doi.org/10.1371/journal.pmed.1000097.

Article  PubMed  PubMed Central  Google Scholar 

Jadad AR, Moore RA, Carroll D, et al. Assessing the quality of reports of randomized clinical trials: is blinding necessary? Control Clin Trials. 1996;17(1):1–12. https://doi.org/10.1016/0197-2456(95)00134-4.

Article  CAS  PubMed  Google Scholar 

R Core Team (2020). R: A language and environment for statistical computing. Vienna: R Foundation for Statistical Computing. URL https://www.R-project.org/.

Suzuki T, Uchida H, Watanabe K, et al. How effective is it to sequentially switch among Olanzapine, Quetiapine and Risperidone? A randomized, open-label study of algorithm-based antipsychotic treatment to patients with symptomatic schizophrenia in the real-world clinical setting. Psychopharmacology. 2007;195(2):285–95. https://doi.org/10.1007/s00213-007-0872-2.

Article  CAS  PubMed  Google Scholar 

Kinon BJ, Kane JM, Johns C, et al. Treatment of neuroleptic-resistant schizophrenic relapse. Psychopharmacol Bull. 1993;29(2):309–14.

CAS  PubMed  Google Scholar 

Shalev A, Hermesh H, Rothberg J, Munitz H. Poor neuroleptic response in acutely exacerbated schizophrenic patients. Acta Psychiatr Scand. 1993;87(2):86–91. https://doi.org/10.1111/j.1600-0447.1993.tb03335.x.

Article  CAS  PubMed  Google Scholar 

Kinon BJ, Chen L, Ascher-Svanum H, et al. Early response to antipsychotic drug therapy as a clinical marker of subsequent response in the treatment of schizophrenia. Neuropsychopharmacol. 2010;35(2):581–90. https://doi.org/10.1038/npp.2009.164.

Article  CAS  Google Scholar 

Heres S, Cordes J, Feyerabend S, et al. Changing the antipsychotic in early nonimprovers to amisulpride or olanzapine: randomized, double-blind trial in patients with schizophrenia. Schizophr Bull. 2022;48(6):1273–83. https://doi.org/10.1093/schbul/sbac068.

Article  PubMed  Google Scholar 

Loebel A, Silva R, Goldman R, et al. Lurasidone dose escalation in early nonresponding patients with schizophrenia: a randomized placebo-controlled study. J Clin Psychiatry. 2016;77(12):1672–80. https://doi.org/10.4088/JCP.16m10698.

Article  PubMed  Google Scholar 

Hatta K, Otachi T, Sudo Y, et al. A comparison between augmentation with olanzapine and increased risperidone dose in acute schizophrenia patients showing early non-response to risperidone. Psychiatry Res. 2012;198(2):194–201. https://doi.org/10.1016/j.psychres.2012.01.006.

Article  CAS  PubMed  Google Scholar 

Hatta K, Otachi T, Fujita K, et al. Antipsychotic switching versus augmentation among early non-responders to risperidone or olanzapine in acute-phase schizophrenia. Schizophr Res. 2014;158(1–3):213–22. https://doi.org/10.1016/j.schres.2014.07.015.

Article  PubMed  Google Scholar 

Correll CU, Martin A, Patel C, et al. Systematic literature review of schizophrenia clinical practice guidelines on acute and maintenance management with antipsychotics. NPJ Schizophr. 2022;8(1):5. https://doi.org/10.1038/s41537-021-00192-x.

Article  Google Scholar 

Howes OD, McCutcheon R, Agid O, et al. Treatment-resistant schizophrenia: treatment response and resistance in psychosis (TRRIP) working group consensus guidelines on diagnosis and terminology. Am J Psychiatry. 2017;174(3):216–29. https://doi.org/10.1176/appi.ajp.2016.16050503.

Article  PubMed  Google Scholar 

Correll CU, Citrome L, Haddad PM, et al. The use of long-acting injectable antipsychotics in schizophrenia: evaluating the evidence. J Clin Psychiatry. 2016;77(Suppl 3):1–24. https://doi.org/10.4088/JCP.15032su1.

Article  PubMed  Google Scholar 

Lopez LV, Shaikh A, Merson J, Greenberg J, Suckow RF, Kane JM. Accuracy of clinician assessments of medication status in the emergency setting: a comparison of clinician assessment of antipsychotic usage and plasma level determination. J Clin Psychopharmacol. 2017;37(3):310–4. https://doi.org/10.1097/JCP.0000000000000697.

Article  PubMed  Google Scholar 

McCutcheon R, Beck K, D’Ambrosio E, et al. Antipsychotic plasma levels in the assessment of poor treatment response in schizophrenia. Acta Psychiatr Scand. 2018;137(1):39–46. https://doi.org/10.1111/acps.12825.

Article  CAS  PubMed  Google Scholar 

Rubio JM, Schoretsanitis G, John M, et al. Psychosis relapse during treatment with long-acting injectable antipsychotics in individuals with schizophrenia-spectrum disorders: an individual participant data meta-analysis. Lancet Psychiatry. 2020;7(9):749–61. https://doi.org/10.1016/S2215-0366(20)30264-9.

Article  PubMed  Google Scholar 

Bak M. Monitoring clozapine adverse effects calls for the integration of protocol and good clinical practice. J Clin Psychiatry. 2012;73(10):1313–4. https://doi.org/10.4088/JCP.12com07964.

Article  CAS  PubMed  Google Scholar 

Kane JM, Agid O, Baldwin ML, et al. Clinical Guidance on the Identification and Management of Treatment-Resistant Schizophrenia. J Clin Psychiatry. 2019;80(2):18123. https://doi.org/10.4088/JCP.18com12123.

Article  Google Scholar 

Nielsen J, Nielsen RE, Correll CU. Predictors of clozapine response in patients with treatment-refractory schizophrenia: results from a Danish Register Study. J Clin Psychopharmacol. 2012;32(5):678–83. https://doi.org/10.1097/JCP.0b013e318267b3cd.

Article  CAS  PubMed  Google Scholar 

Thien K, O’Donoghue B. Delays and barriers to the commencement of clozapine in eligible people with a psychotic disorder: a literature review. Early Interv Psychiatry. 2019;13(1):18–23. https://doi.org/10.1111/eip.12683.

Article  PubMed  Google Scholar 

Bachmann CJ, Aagaard L, Bernardo M, et al. International trends in clozapine use: a study in 17 countries. Acta Psychiatr Scand. 2017;136(1):37–51. https://doi.org/10.1111/acps.12742.

Article  CAS  PubMed  Google Scholar 

Bareis N, Olfson M, Wall M, Stroup TS. Variation in psychotropic medication prescription for adults with schizophrenia in the United States. Psychiatr Serv. 2022;73(5):492–500. https://doi.org/10.1176/appi.ps.202000932.

Article  PubMed  Google Scholar 

Potkin SG, Kane JM, Correll CU, et al. The neurobiology of treatment-resistant schizophrenia: paths to antipsychotic resistance and a roadmap for future research. NPJ Schizophr. 2020;6(1):1. https://doi.org/10.1038/s41537-019-0090-z.