Recent findings suggest that functional irregularities in oxytocin biology may play a role in the pathophysiology of depression. One of the proposed pathways is related to stress, as oxytocin exerts a regulatory effect over neuroendocrine stress axis. Moreover, stress exposure and stress axis dysregulation are likely connected to dissociative symptoms.

Therefore, the study investigates the relationship between depression severity, stress symptoms levels, dissociation and plasma oxytocin levels.

Depression severity was assessed by Beck Depression Inventory (BDI-II), symptoms related to stress were assessed by Trauma Symptom Checklist (TSC-40), psychological and somatoform dissociative symptoms were assessed by Dissociative Experiences Scale (DES) and Somatoform Dissociation Questionnaire (SDQ-20), respectively. Plasma oxytocin was measured using radioimmunoassays.

69 patients were included in the study, 34 in severe depression group (BDI-II≥29) and 35 in mild to moderate depression group (BDI-II≤28). the groups did not differ significantly in oxytocin levels. in severe depression group, negative correlations between oxytocin and TSC-40 and SDQ-20 were found (R = −0,55; p < 0,01 and R = −0,35; p < 0,05, respectively). Interestingly, no significant correlation was found between oxytocin and BDI-II.

The negative correlation between oxytocin and symptoms related to trauma and somatoform dissociation in severe depression group is, to our knowledge, the first finding in this context. It is consistent with stress-reducing effect of oxytocin in acute stress paradigms and suggests that stress and somatoform dissociation may represent important factors in complex relationship linking oxytocin to depression. the directionality of these relationships need to be assessed in longitudinal studies.