Activity of the hypothalamic-pituitary-adrenal axis and inflammatory mediators in major depressive disorder with or without metabolic syndrome.

BACKGROUND: The aim of the present study was to explore the differences in serum CRP, IL-6, TNF-α, ACTH and cortisol among patients with major depressive disorder with or without metabolic syndrome (MS) compared to a healthy control group.

SUBJECTS AND METHODS: The MDD study group consisted of 80 patients (mean age of 50.03±9.55 years). The control group was recruited from the hospital personnel and it consisted of 40 examinees (mean age of 47.20±7.99 years). All patients who participated in the study were diagnosed with depressive disorder using MINI questionnaire, and Hamilton rating scale for depression. Diagnosis of the metabolic syndrome was set by NCEP ATP III criteria.

RESULTS: Examinees with depression but without MS had significantly more cortisol concentration when compared to the control group. CRP was significantly higher in the MDD group when compared to the control group and in MDD+MS group when compared to the control group. IL6 serum levels were significantly higher in the MDD group when compared to the healthy control group, and in MDD+MS group when compared to the healthy control group. ACTH had significant independent predictive values for abdominal obesity. Levels of TNF-α were statistically significant independent predictors for hyperglycaemia. Statistically significant predictive values for MDD were found for cortisol, and IL-6.

CONCLUSION: Results shown here emphasise the importance of neuroendocrine and inflammatory factors in pathogenesis of depressive disorder and MS. Further prospective research is necessary to clarify possible causal relationship between depression and MS. It is necessary to investigate the possibility of a joint biological mechanism in pathogenesis of these two disorders with the special attention given to the disturbances in the immune system.