Distinct physiological responses to social-evaluative stress in patients with major depressive disorder reporting a history of peer victimization

Peer victimization is a risk factor for the development of major depressive disorders, but little is known about the mechanisms. This study examined whether peer victimization alters physiological and affective responses to potentially threatening social stimuli. For this purpose, reactions to socially evaluative stimuli of depressive patients and healthy controls with varying histories of peer victimization were compared. In a social conditioning task, we studied heart rate responses to unconditioned socially negative and neutral evaluative video statements, followed by the heart rate reactions to conditioned stimuli, i.e. still images of the faces of the same actors. Diagnosis of depression and peer victimization were both associated with a more pronounced heart rate deceleration in response to unconditioned stimuli, irrespective of valence. The effect of peer victimization was stronger in depressive patients than in healthy controls. However, heart rate responses to the CSs were not related to depression or peer victimization. The results indicate a hypervigilant processing of social stimuli in depressive patients reporting histories of peer victimization. This distinct processing may be associated with inappropriate behavioral and emotional responses to social challenges, putting individuals at risk for depressive symptoms.