Rates of treatment-resistant schizophrenia from first-episode cohorts: systematic review and meta-analysis

• Published in: British journal of psychiatry 2022-03, Vol.220 (3), p.115-120
• Main Authors: Siskind, Dan, Orr, Stacy, Sinha, Surabhi, Yu, Ou, Brijball, Bhavna, Warren, Nicola, MacCabe, James H, Smart, Sophie E, Kisely, Steve
• Format: Article
• Language: English
• Subjects: Access; Antipsychotic Agents - therapeutic use; Bias; Clozapine; Clozapine - therapeutic use; Cross-Sectional Studies; Data collection; Dropping out; Female; Functional impairment; General Adult; Health care; Humans; Male; Mental disorders; Meta-analysis; Patients; Psychiatry; Psychosis; Psychosocial factors; Psychotropic drugs; Recruitment; Relapse; Remission (Medicine); Resource allocation; Retrospective Studies; Review; Reviews; Schizophrenia; Schizophrenia - drug therapy; Schizophrenia - epidemiology; Schizophrenia, Treatment-Resistant; Selection bias; Sensitivity analysis; Statistical analysis; Systematic review; Working groups
• ISSN: 0007-1250; 1472-1465
• DOI: 10.1192/bjp.2021.61

Treatment-resistant schizophrenia (TRS) is associated with high levels of functional impairment, healthcare usage and societal costs. Cross-sectional studies may overestimate TRS rates because of selection bias. We aimed to quantify TRS rates by using first-episode cohorts to improve resource allocation and clozapine access. We undertook a systematic review of TRS rates among people with first-episode psychosis and schizophrenia, with a minimum follow-up of 8 weeks. We searched PubMed, PsycINFO, EMBASE, CINAHL and the Cochrane Database of Systematic Reviews, and meta-analysed TRS rates from included studies. Twelve studies were included, totalling 11 958 participants; six studies were of high quality. The rate of TRS was 22.8% (95% CI 19.1-27.0%, P < 0.001) among all first-episode cohorts and 24.4% (95% CI 19.5-30.0%, P < 0.001) among first-episode schizophrenia cohorts. Subgroup sensitivity analyses by location of recruitment, TRS definition, study quality, time of data collection and retrospective versus prospective data collection did not lead to statistically significant differences in heterogeneity. In a meta-regression, duration of follow-up and percentage drop-out did not significantly affect the overall TRS rate. Men were 1.57 times more likely to develop TRS than women (95% CI 1.11-2.21, P = 0.010). Almost a quarter of people with first-episode psychosis or schizophrenia will develop TRS in the early stages of treatment. When including people with schizophrenia who relapse despite initial response and continuous treatment, rates of TRS may be as high as a third. These high rates of TRS highlight the need for improved access to clozapine and psychosocial supports.