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

Background: 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.

Aims: We aimed to quantify TRS rates by using first-episode cohorts to improve resource allocation and clozapine access.