The Neural Correlates of Social Appraisal Dysfunction in Major Depressive Disorder: An Event-Related Potential Study

Background: Research has demonstrated that some individuals with major depressive disorder (MDD) exhibit more distorted social appraisal than non-depressed individuals. This study aimed to explore the neuroelectrophysiological mechanisms of emotional processing bias in patients with MDD and thus to understand their functional properties of social appraisal. Methods: Thirty-four patients with MDD and 34 healthy controls (HCs) were selected. The behavioral and event-related potentials (ERPs) data of the Socio-emotional Preference Task (SePT) were recorded and analyzed. Results: The behavioral results showed that t he MDD group showed longer reaction times (RTs) to both negative and positive stimuli compared to the HCs group, preferring negative stimuli. The ERP data indicated that the MDD group exhibited higher P200 amplitudes for negative and neutral stimuli compared to the HCs group. Additionally, they showed higher LPP amplitudes for negative and positive stimuli, with longer LPP latencies for negative stimuli. In the MDD group, multiple linear stepwise regression analysis showed that LPP amplitudes were positively correlated with RTs for positive stimuli and negatively correlated with RTs for negative stimuli. Conversely, P200 amplitudes were negatively correlated with RTs for negative stimuli but positively correlated with Hamilton Depression Rating Scale (HDRS-17) scores. Moreover, HDRS-17 scores positively correlated with the self-reported preference for negative stimuli but negatively correlated with the self-reported preference for positive stimuli. Conclusion: Patients with MDD tend to choose negative information that is consistent with negative self-schema. The brain devotes more cognitive resources and longer RTs to processing negative stimuli, starting from the early stages (P200) and extending into the later stages (LPP), there is a tendency for processing fixation. RTs of patients with MDD to negative and positive stimuli can predict the amplitudes of LPP. Additionally, their preference for negative stimuli and avoidance of positive stimuli can predict depressive symptom severity.