Effects of social exclusion on emotions and oxytocin and cortisol levels in patients with chronic depression

Objective: Patients with chronic depression (CD) experience a high burden of disease, severe comorbidity, and increased mortality. Although interpersonal dysfunction is a hallmark of CD, the underlying mechanisms are largely unexplored. Oxytocin (OT) has been proposed to play a crucial role in the social deficits of mental disorders and has been found to be dysregulated after social exclusion (ostracism) in patients with borderline personality disorder. This study investigated how social exclusion affects emotions, OT levels, and cortisol (CT) levels in CD patients. Method: Twenty-one patients diagnosed with CD and 21 healthy controls (HC) matched for gender, age, and education underwent repeated neuroendocrine measurements in a standardized laboratory setting while playing Cyberball, a virtual ball-tossing game that mimics a social exclusion situation. Emotional reactions, plasma OT and cortisol levels were assessed at baseline and 5, 15, and 40 min after Cyberball. Results: At baseline, there were no group differences in OT levels. Immediately after playing Cyberball, plasma OT levels showed divergent changes in CD patients and HC; the difference in direction of change was significant with a reduction in CD patients compared to HC (p ¼ .035*); CT levels did not differ between groups at any time point, but decreased over time. Patients showed more threatened emotional needs and increased negative emotions, especially anger and resentment, and showed higher sensitivity to ambiguous threat of social exclusion than healthy controls. Conclusions: CD patients react to ostracism with pronounced negative emotions. The reduction in OT levels in CD patients after social exclusion may contribute to their interpersonal dysfunction and their difficulty in coping adequately with aversive social cues.