The Interaction of Oxytocin and Social Support, Loneliness, and Cortisol Level in Major Depression.
Objective
Loneliness is a specific risk factor for depressive symptoms and suicidal behavior. The present study examined whether the serum oxytocin level would interact with social support and buffers loneliness and hypothalamic-pituitary-adrenal (HPA)-axis activity in drug-naïve patients with major depressive disorder (MDD).


Methods
Twenty-six patients with MDD (male:female = 3:23; mean age, 45.54 ± 12.97 years) were recruited. The 17-item Hamilton Depression Rating Scale, UCLA Loneliness Scale and self-reported Measurement of Support Function Questionnaire were administered. Serum oxytocin and cortisol levels were assessed using a commercial immunoassay kits.


Results
In MDD patients, a negative association was found between degrees of social support and loneliness (β= -0.39, p = 0.04). The interaction between social support and serum oxytocin level was negatively associated with loneliness (β= -0.50, p = 0.017) and serum cortisol level (β= -0.55, p = 0.020) after adjusting for age. Follow-up analyses showed that the association between higher social support and lower loneliness was observed only in the higher-oxytocin group (r = -0.75, p = 0.003) but not in the lower group (r = -0.19, p = 0.53). The significance remained after further adjusting for sex and depression severity.


Conclusion
Low oxytocin level is a vulnerability factor for the buffering effect of social support for loneliness and aberrant HPA-axis activity in MDD patients.
['Tsai|Tsung-Yu|TY|', 'Tseng|Huai-Hsuan|HH|', 'Chi|Mei Hung|MH|', 'Chang|Hui Hua|HH|', 'Wu|Cheng-Kuan|CK|', 'Yang|Yen Kuang|YK|', 'Chen|Po See|PS|']
Oxytocin Loneliness Cortisol Major depressive disorder Social support.