Evaluation of malondialdehyde, superoxide dismutase and catalase activity and their diagnostic value in drug naïve, first episode, non-smoker major depression patients and healthy controls.

Major depression is a most frequent disorder, its diagnosis depends on patient interview, and yet we do not have a reliable biomarker for depression. Oxidative stress is defined as increase in oxidation or decrease is antioxidant defense mechanisms. Here, we aimed to investigate malondialdehyde (MDA), superoxide dismutase (SOD) and catalase (CAT) activity and their diagnostic performance in depressed patients and healthy controls. We collected blood samples from 50 patients and 50 controls. We found MDA levels were significantly higher in the patients than controls, with medians at 4.04nmol/mg and 1.64nmol/mg, respectively, p<0.001. SOD activity was significantly decreased in depressed patients than healthy controls, with means at 143.50U/mg and 298.12U/mg, respectively, p<0.001. CAT activity was similar in both groups, p=0.517. ROC analysis showed good diagnostic value for MDA and SOD, with the area under the curve at 1.0 for both. We found high correlation between SOD and Ham-D scores (r=0.747, p<0.0001) and between MDA and Ham-D scores (r=0.785, p<0.0001). Overall, these results demonstrate that oxidative stress is increased in depressed patients. MDA increase seem to be a common finding for major depression. We believe MDA could be a good biomarker candidate for major depression, but not SOD. Future studies should focus on the diagnostic value of MDA in larger samples.