Correlation of Severity of Depression with a Novel Inflammatory Marker: Neutrophil to Lymphocyte Ratio

Abstract

Introduction: Many new inflammatory markers are being extensively used recently for assessing the severity and prognosis of chronic conditions. Neutrophil-Lymphocyte ratio (NLR) because of its simplicity and affordability stands out. Its applicability to psychiatric disorders specifically Depression is an eye-opener. Hamilton Rating Scale for Depression (HAM-D), a clinician-based scoring system is better among other self-scoring systems where the study population is semi-illiterate. Materials and Method: Total of 80 patients over a period of 1 year presenting to psychiatric OPD with depressive symptoms were evaluated for the severity of Major Depressive Disorder (MDD) using HAM-D scale. A score of 7-17, 18-24 and >25 was categorised under mild, moderate, and severe degrees respectively. NLR was calculated and was correlated with their severity. Statistical analysis was done using PSPP software and p value of <0.05 was considered significant. Results: Out of the 80 patients 45 were females and 35 were males. The average age was 35.41 years ± 10.13 SD. 23 patients categorised under mild depression had mean NLR of 1.56 ± 0.46 SD, 40 patients with moderate depression and 17 patients with severe depression had mean NLR of 2.70 ± 1.08 SD and 4.62 ± 1.31 SD respectively. The mean value of NLR for patients of severe depression lied in the Mild-Moderate Inflammation zone (3-7). P-value was <0.05 and was considered significant. Discussion: A novel and easy biomarker like NLR can be as useful as assessing Inflammatory Cytokines like IL-6, IL-1 and TNF-α for assessing the severity of MDD. Rise of cortisol in persistent stress favours an increase in neutrophils and a reduction in lymphocytes, and thus, increased NLR. Thus, a rise of NLR with increasing severity of Depression could become a robust tool in future for predicting mortality and severity in patients suffering from MDD.