The present event-related potential (ERP) study investigated for the first time whether children with early-onset social anxiety disorder (SAD) process affective facial expressions of varying intensities differently than non-anxious controls. Participants were 15 SAD patients and 15 non-anxious controls (mean age of 9 years). They were presented with schematic faces displaying anger and happiness at four intensity levels (25%, 50%, 75%, and 100%), as well as with neutral faces. ERPs in early and later time windows (P100, N170, late positivity [LP]), as well as affective ratings (valence and arousal) for the faces, were recorded. SAD patients rated the faces as generally more arousing, regardless of the type of emotion and intensity. Moreover, they displayed enhanced right-parietal LP (350-650 ms). Both arousal ratings and LP reflect stimulus intensity. Therefore, this study provides first evidence of an intensity amplification bias in pediatric SAD during facial affect processing.
Keywords: ERP; Social anxiety; emotion intensity; facial expression; late positivity.