The time course of affective processing in anhedonia: Insights from event-related potentials

Anhedonia, defined as a diminished capacity to experience pleasure from appetitive stimuli, is a core symptom of depression and a predisposing factor for its development. Prior research links anhedonia with blunted emotional processing of appetitive stimuli. Yet, emotional processing encompasses multiple stages (cue engagement, affective anticipation, and elaboration), and how each stage relates to anhedonia remains unclear. This study examined these associations in a sample of university students (n = 45, 31 females) with varying levels of anhedonia. Participants underwent electroencephalography recording during an S1-S2 paradigm, in which a cue (S1) anticipated the valence (pleasant, neutral, unpleasant) of an upcoming emotional image (S2). Three event-related potentials (ERPs) were assessed: the Cue-P300 (reflecting cue evaluation and engagement), the Stimulus Preceding Negativity (SPN; reflecting affective anticipation), and the Late Positive Potential (LPP; reflecting affective elaboration). While the LPP was larger for emotional vs. neutral images, the Cue-P300 and the SPN were more pronounced for pleasant (but not unpleasant) vs. neutral stimuli. Notably, anhedonia, independent of other depressive symptoms, was associated with an increased SPN and a blunted LPP for pleasant stimuli. These findings suggest a complex pattern of emotional processing in anhedonia, marked by increased anticipation but reduced elaboration of appetitive stimuli.