Executive dysfunction and cognitive disorganization in schizophrenia: Case-control and cluster analyses of a Korean Wisconsin Card Sorting Test cohort.

OBJECTIVE

Executive dysfunction is a hallmark cognitive deficit in schizophrenia, yet phenotypic heterogeneity within the disorder complicates clinical translation. This study aimed to identify discrete executive profiles within a large Korean schizophrenia cohort using the Wisconsin Card Sorting Test (WCST) and to evaluate their clinical and functional correlates.

METHOD: We analyzed WCST performance in 276 individuals with schizophrenia and 361 healthy controls. A principal component analysis (PCA)-derived executive composite was validated against chart-reviewed clinical variables in a patient subset (n = 145). K-means cluster analysis was utilized to characterize cognitive heterogeneity, stratifying patients into distinct neurocognitive profiles.

RESULTS

Patients with schizophrenia exhibited severe, broad executive impairment compared to controls, particularly in total errors (Hedges' g = 2.268), categories achieved (g = 2.122), and conceptual-level responses (g = 1.751). Within the patient group, cluster analysis robustly identified three distinct executive profiles: mild/near-normal (n = 83), intermediate (n = 88), and severe (n = 105). While age was independently associated with the general executive dysfunction composite (β = 0.254, p = 0.004), conceptual disorganization showed a prominent, theoretically consistent trend-level association (β = 0.166,p = 0.065). Exploratory neurodevelopmental burden and mediation pathways did not show robust statistical signals.

CONCLUSIONS

Executive dysfunction in schizophrenia is characterized by reproducible, clinically interpretable sub-profiles rather than a uniform deficit. Stratifying patients into mild, intermediate, and severe executive clusters provides a practical framework for neurocognitive heterogeneity, which may facilitate target selection for individualized cognitive remediation and functional rehabilitation strategies.