Instruments for assessing insight in psychosis: A systematic review of psychometric properties

Insight into psychosis is a multidimensional construct involving awareness of illness, attribution of symptoms, and perceived need for treatment. Despite extensive research, substantial variability in how insight is conceptualized and measured continues to hinder clinical assessment and cross-study comparisons.

Following Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guidelines and a registered International Prospective Register of Systematic Reviews protocol (CRD42024558386), we conducted a systematic search across five databases (n = 2,184). Twenty-nine studies met the inclusion criteria, comprising 15 primary scale development papers and 10 independent validation studies. We included instruments explicitly designed to assess insight in schizophrenia-spectrum, and evaluated them using the COnsensus-based Standards for the selection of health Measurement INstruments Risk of Bias checklist. Psychometric domains assessed included content validity, structural validity, construct validity, criterion validity, internal consistency, reliability, responsiveness, and interpretability.

Fifteen distinct insight scales were identified, comprising nine clinician-rated instruments, five self-report tools, and one hybrid format. Most demonstrated adequate content and structural validity, with 11 achieving 'very good' reliability ratings. Four scales showed the strongest overall psychometric support. However, responsiveness to clinical change was rarely tested, and cross-cultural validation remained limited. Earlier instruments primarily emphasized clinician-rated illness awareness, whereas more recent tools incorporated cognitive, neurocognitive, and subjective dimensions. Discrepancies between self-report and clinician ratings were common and often clinically meaningful. These findings underscore the need for multidimensional, psychometrically robust, and context-sensitive tools to advance both clinical assessment and research on insight in psychotic disorders.