Study on Inflammatory Link between Stress and Major Depressive Disorder: An Approach through the Biochemical Lens

Background: The relationship between depression and inflammation has been strengthened by different studies for which chronic stress leading to HPA axis activation and cortisol secretion has been proposed to explain pathogenesis of depression.

Objective: To estimate and evaluate level of cortisol, Ferritin and hsCRP in serum of the patients suffering from Major Depressive disorder and healthy control.

Methods: The role of cortisol and inflammation in Major Depressive Disorder (MDD) has been evaluated in this study among 150 patients suffering from MDD along with 150 age and sex matched control subjects. Serum cortisol and two well-known acute phase reactant proteins namely hsCRP and Ferritin were assayed in all study subjects by Enzyme Immuno Assay method.

Results: Cortisol and hsCRP concentrations in serum were found to be significantly higher in all MDD patients, whereas ferritin levels were found to be significantly lower. There was no significant difference in the parameters among different grades of MDD. The ROC curve was used to assess the viability of using these three parameters as biomarkers. Gender wise comparison of the parameters showed that significant difference is present in the level of Ferritin only.

Conclusion: The significant change in biochemical parameters which is not associated with grade wise alteration suggests that probably inflammation is the early event which causes depression. As a result, there is no gradual change as the severity of the disease increases. Considering Area under curve in both female and male, hsCRP seems to be the biomarker that can be used in MDD cases.