Time-resolved EEG decoding reveals altered neural dynamics of affective semantic evaluation in depression and suicidality

Depression and suicidality are associated with systematic alterations in cognitive and emotional processing, yet the spatiotemporal neural dynamics underlying these changes during affective task engagement remain poorly characterized. We investigate the time-resolved neural representations of affective semantic processing using multivariate decoding of 64-channel electroencephalography (EEG), while participants (N = 137) perform Sentence Evaluation task using emotionally salient, self-referential statements. Reliable condition-dependent neural discriminability emerges with peak decoding accuracy between 300-600 ms, a time window corresponding to affective semantic evaluation, contextual updating processes, and conflict monitoring. Relative to healthy controls, individuals with depression and suicidal ideation show earlier onset, longer duration, and greater amplitude decoding responses, along with broader cross-temporal generalization and enhanced contributions from frontocentral and parietotemporal components. These results indicate systematic group-level differences in the spatiotemporal dynamics and stability of neural representations during emotionally salient semantic evaluation, contributing to a characterization of neurocognitive processes associated with depression and suicidality.