As treatment resistance makes the management of schizophrenia more complicated, researchers sought to analyze current approaches to develop consensus criteria and guidelines through a systematic review of randomized clinical trials of antipsychotics in treatment resistant schizophrenia. A total of 42 of the studies met inclusion criteria, of which 21 did not have operationalized criteria. The others, however, had varied criteria among symptom severity, previous duration of treatment, and thresholds of antipsychotic dose. Two studies had the same criteria.

The group of researchers recognized criteria that was both minimum and optimal, using principles including present symptoms of minimum duration and severity based on a standardized rating scale, at least moderate functional impairment, previous treatment of at least 2 antipsychotic trials, assessment of adherence, at least 1 prospective treatment trial, and measures that distinctively separated patients who were responsive and treatment resistant. There is a significant variation of approaches in defining treatment resistance in schizophrenia. The researchers present consensus guidelines to operationalize criteria in establishing and reporting resistance of treatment, adequate treatment, and response of treatment in schizophrenia in order to deliver a standard in research and clinical translation.

Reference: 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):216-229. doi:10.1176/appi.ajp.2016.16050503