Ostracism (social exclusion) has been found to be a remarkable stress factor to mentally ill people with difficulties in situations of social interaction. In an earlier study it was found that patients with borderline personality disorder (BPD) showed differences in oxytocin dysregulation by having lower oxytocin plasma levels during a social exclusion paradigm (Jobst et al., 2013, submitted). To our knowledge, this is the first study investigating neuroendocrinological changes of social exclusion in chronically depressed patients. Chronic depression (CD) is associated with poor social functioning and behavioral interpersonal problems which are considered to be based on the non-responsiveness of CD patients to environmental consequences.

To manipulate a situation of social exclusion we used the Cyberball Paradigm, a virtual ball tossing game which has been well validated and applied in numerous previous studies on the effects of social exclusion. 19 CD patients (according to DSM-IV) and 19 healthy controls matched for gender, age and education underwent repeated neuroendocrine measurements in a standardized laboratory setting during the Cyberball Paradigm. Assessments of psychological variables as well as measurements of oxytocin plasma levels were performed at baseline, 5 min, 15 min and 40 min after Cyberball.

As an association of interpersonal problems in BPD with oxytocin dysregulation has been found, we suggest differences in changes of oxytocin levels in a social exclusion situation in CD patients versus healthy subjects. The data will be presented and discussed in relation to specific interpersonal problems of patients suffering from CD.