Is the neutrophil-to-lymphocyte ratio indicating inflammation in bipolar disorder?

Objective: Neutrophil-to-lymphocyte ratio (NLR) has been shown to be a useful marker of inflammation in many inflammatory diseases. NLR may be a useful marker to determine an inflammatory state during Bipolar Disorder (BD) episodes. The aim of the current study is to determine the inflammation during BD episodes, using NLR as an indicator of inflammation.

Methods: 157 patients with bipolar disorder were included in this cross-sectional study. The NLR was calculated from the differential count, dividing the absolute neutrophil count by the absolute lymphocyte count. Inclusion criteria for neutrophil and lymphocyte counts were being in the 2500-7500/mm3 and 1500-3500/mm3 interval, respectively. Patients with end stage renal disease, malignant diseases, severe liver failure, active infection diseases, and active smoking were excluded from the study.

Results: NLR levels were highest in patients with manic episode and lowest in the control group (2.68±1.27, 1.82±0.65). ESR and CRP levels of manic patients were significantly higher than other groups (p=0.261, p=0.199).

Conclusion: NLR during periods of mania is higher than during depression and euthymic periods of the BD. It is possible to say that the degree of the inflammation during the period of disease could be different, and exacerbation of inflammation during the period of mania in BD could explain systemic cardiovascular comorbidities of disorder.