Executive function (EF) impairment represents a core feature of schizophrenia, yet how specific EF dimensions differ across illness stages remains poorly understood. This study aimed to characterize the differential profiles of three EF dimensions between first-episode schizophrenia (FES) and chronic schizophrenia (ChSz) patients, and to identify which dimensions most strongly differentiate between these illness stages.
MethodsA total of 182 schizophrenia patients (85 FES, illness duration ≤ 2 years; 97 ChSz, illness duration ≥ 5 years) completed five behavioral paradigms assessing inhibitory control, working memory, and cognitive flexibility. Mixed-model ANCOVA examined differential EF impairment patterns between groups. Random forest classifiers with nested cross-validation and Shapley Additive Explanations (SHAP) were employed to determine the relative multivariate importance of EF dimensions in distinguishing between illness stages.
ResultsMixed-model ANCOVA revealed a significant group-by-dimension interaction. FES patients exhibited milder deficits in inhibitory control and working memory updating compared to ChSz patients (all pfdr < 0.05), with the largest effect size for interference inhibition (η² = 0.140). Correlation analyses linked EF impairments to illness duration, symptom severity, and antipsychotic dosage. SHAP analysis identified interference inhibition and working memory updating as the dimensions most strongly associated with illness stage.
ConclusionsThis study revealed stage-specific EF impairment profiles in schizophrenia, with inhibitory control and working memory updating showing the greatest differences between FES and ChSz patients. These dimensions may serve as sensitive markers for differentiating illness stages and represent potential targets for stage-specific cognitive interventions.
