Neutrophil-to-lymphocyte ratio: A potential new peripheral biomarker of suicidal behavior

Abstract

Background. Neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), and platelet-to-lymphocyte ratio (PLR) have emerged as important peripheral inflammatory biomarkers. Recent data suggest a possible role of the immune system in the pathophysiology of suicidal behavior (SB). The aim of this study is to evaluate the association among NLR, MLR, and PLR and SB in patients with major depressive disorder (MDD), and to test its validity as a biomarker for suicidality. Methods. We evaluated 538 patients with MDD (mean age [standard deviation] = 43.87 [14.36] years; females: 68.8%). A logistic regression model was estimated to determine the independent factors associated with suicide risk in patients with and without a history of suicide attempt (SA). Results. Three hundred ninety-three patients (74.7%) had a personal history of SA. Patients with a previous SA were more frequently female (71.9% vs. 59.6%; p = 0.007), significantly younger (41.20 vs. 51.77 years; p < 0.001), had lower depression severity at enrolment (15.58 vs. 18.42; p < 0.000), and significantly higher mean NLR and PLR ratios (2.27 vs. 1.68, p = 0.001; 127.90 vs. 109.97, p = 0.007, respectively). In the final logistic regression model, after controlling for age, sex, and depression severity, NLR was significantly associated with SB (β = 0.489, p = 0.000; odds ratio [95% confidence intervals] = 1.631 [1.266–2.102]). We propose a cut-off value of NLR = 1.30 (sensitivity = 75% and specificity = 35%). Conclusions. Our data suggest that NLR may be a valuable, reproducible, easily accessible, and cost-effective strategy to determine suicide risk in MDD.

Neutrophil‐to‐lymphocyte ratio and C‐reactive protein in non‐fatal suicidal attempts: A cross‐sectional pilot study in Bangladesh

“…It has been revealed that NLR is a potential biomarker of suicidality in patients with major depressive illness and it was suggested that NLR might be used to predict suicide risk in patients with depression. 10 NLR was also shown to be higher among individuals who tried suicide in both depression and suicide groups, according to another study. 11 It has been proposed as a marker of low‐grade systemic inflammation in mental disorders, and preliminary evidence reveals that NLR is higher in suicide attempters with and without psychiatric morbidity than in the control group.…”

Suicide prevention in childhood and adolescence: a narrative review of current knowledge on risk and protective factors and effectiveness of interventions

“…Inflammation parameters recently emerged as a potential biomarker for suicidal behavior in adults with both major depression and bipolar disorder (Ekinci & Ekinci, 2017; Ivkovic et al, 2016; Velasco et al, 2020). Similarly, Pandey et al (2012) found an increase in proinflammatory cytokine post‐mortem in the brain of teenagers who had died from suicide.…”

Association Between Systemic Immune-Inflammation Index and Diabetic Depression

“…15 Inflammatory biomarkers could potentially be used to predict depression in diabetic patients. Abnormal increases in inflammatory blood cell parameters including neutrophil count, neutrophil-to-lymphocyte ratio, 16,17 monocyte-to-lymphocyte ratio, 18 and platelet-tolymphocyte ratio 19,20 serve as simple markers of inflammation and their ability to predict depression has been assessed. But these biomarkers involve only two types of immune-inflammatory cells and might not accurately reflect the inflammation status.…”