A norm-anchored framework for characterizing cognitive heterogeneity in schizophrenia

Cognitive heterogeneity is a core feature of schizophrenia (SCZ). Conventional approaches examine this heterogeneity using domain-specific scores, which may not fully reflect the underlying cognitive structure. In this study, a norm-anchored cognitive structural deviation (NCSD) framework was developed to examine such heterogeneity from a structure-informed perspective. The HC-derived latent cognitive structure (N-LCS) captured performance across the assessed tasks and remained stable under external validation in an independent cohort. Patients with SCZ showed greater global deviation from the N-LCS, along with altered loading directions of Wisconsin Card Sorting Test (WCST)-derived executive indicators which were consistent across robustness analyses, and altered correlation patterns among cognitive measures relative to HC. These features were quantified using three NCSD-derived indices: the cognitive normative deviation index (CNDI), loading pattern divergence (LPD), and correlation structure discrepancy (CSD). CNDI discriminated SCZ from HC with stable performance under cross-validation. LPD and CSD were associated with anxiety ratings, with LPD also showing a trend-level association with positive symptoms. Exploratory clustering identified a three-cluster solution with clear separation and moderate stability. Together, these findings show that cognitive heterogeneity in SCZ involves both global deviation from the N-LCS and structural alteration. NCSD provides a refined framework to characterize such heterogeneity and may inform precision psychiatry and functional recovery.