The Modulation of Oxytocin and Cortisol Levels in Major Depression Disorder and Irritable Bowel Syndrome

There is a progressive trend in the current literature in understanding the central effects of oxytocin, which besides its classical roles in parturition and lactation, seems to exert some facilitatory effects in most of the neuropsychiatric disorders. Thus, it seems that oxytocin is mainly linked to the neuropsychiatric disorders where the social component is more or less affected and it has also strong correlations with the stress-related mechanisms and hypothalamic�pituitary�adrenal (HPA) axis. In addition, the connections between oxytocin and the digestive system were previously suggested, including by some of our preliminary results, in the context of irritable bowel syndrome (IBS) pathology. Also, the relations between depression and stress in the context of cortisol implications are quite well described, although various modifications of cortisol (increased, decreased or non-modified) were described in the major depression pathology. Thus, by using two research cohorts: one with major depression disorder (n = 15) and another one having both diagnosis of major depression disorder and irritable bowel syndrome in the same time (n = 15), we are showing in this report significantly increased levels of cortisol in patients with MDD and IBS, when compared with patients with MDD without IBS, while an opposite pattern was obtained by measuring the plasma level of oxytocin, where the patients with MDD and IBS had a significantly decreased concentration of oxytocin, as compared with those with MDD but without IBS.