Social cognitive impairment across the bipolar disorder continuum: A comparative study of high-risk, first-episode,...

This study investigates whether social cognitive deficits in bipolar disorder (BD) represent static susceptibility markers, underlying differences in severity and vulnerability or graded, stage-related differences, thereby testing the clinical staging hypothesis. A healthy control (HC; n = 97) group was utilized as a normative reference to calculate Z-scores. The main analyses then compared four clinical and risk groups: chronic bipolar disorder (BD; n = 33), first-episode BD (FE-BD; n = 69), ultra-high-risk for BD (UHR-BD; n = 86), and familial high-risk for BD (FHR-BD; n = 70). Five subdomains were assessed: Emotion recognition (ER), attributional bias (AB), theory of mind (ToM), social knowledge (SK), and social perception (SP). Between-group differences and linear trends across stages were analyzed. Significant between-group differences emerged in ER, SK, and ToM, with SP approaching significance. Crucially, graded between-group differences (linear trends) from high-risk stages to chronic illness were observed across all capacity-based domains (ER, ToM, SK, and SP). The most pronounced performance deficits occurred in the FE-BD and chronic BD groups. Conversely, AB demonstrated no significant group differences or linear trends. These findings are compatible with clinical staging models in BD. Longitudinal studies are necessary to establish whether these stage-related differences reflect true progression or baseline differences related to the underlying level of vulnerability.