Can Neutrophil Lymphocyte Ratio Predict the Likelihood of Suicide in Patients with Major Depression?

Peripheral blood cellular immunophenotype in suicidal ideation, suicide attempt, and suicide: a systematic review and meta-analysis

Previous meta-analyses have documented the association of immune-inflammatory pathways with the pathophysiology of Major Depressive Episode (MDE), as reflected by alterations in peripheral blood immune cell counts. However, it remains unclear whether these immunological changes are distinct in individuals experiencing suicidal ideation (SI) or suicidal behavior (SB), beyond the context of an MDE. This systematic review and meta-analysis aimed to examine peripheral immune cell profiles across samples with SI/SB and compare them to healthy controls or patients with MDE. A systematic literature search was conducted in MEDLINE, Embase, and PsycINFO for articles published from inception until June 12, 2023. Two independent reviewers screened the articles for inclusion, extracted data, and assessed the risk of bias using the Newcastle-Ottawa scale. Meta-analyses were performed using a random-effects model to calculate standardized mean differences (SMDs) and 95% confidence intervals (CIs) for immune cell counts or ratios between groups with and without SI/SB. Heterogeneity across studies was assessed using the restricted maximum-likelihood estimator for tau statistic and I2-statistic and tested by the Q test. Publication bias was evaluated using the Egger´s test and funnel plots. Meta-regression analyses were conducted to explore the potential moderating effects of age, gender, current or lifetime SI/SB, and the type of self-harming behavior (SI or SB). The study was registered with PROSPERO (CRD42023433089). The systematic review included 30 studies, with data from 19 studies included in the meta-analyses comprising 139 unique comparisons. Eleven different cell populations or ratios were included, comprising 1973 individuals with SI/SB and 5537 comparison subjects. White blood cell (WBC) and neutrophil counts were higher in individuals with SI/SB than in controls (WBC: SMD = 0.458; 95% CI = 0.367-0.548; p value ≤ 0.001; I2 = 0.002% and; Neutrophils: SMD = 0.581; 95% CI = 0.408-0.753; p < 0.001), indicating an inflammatory process. The neutrophil-to-lymphocyte ratio (NLR) emerged as a potential marker, demonstrating a notable elevation in individuals with SI/SB (SMD = 0.695; 95% CI = 0.054-1.335; p value = 0.033; I2 = 94.281%; Q test p value ≤ 0.001). The elevated NLR appears to be primarily driven by the increase in neutrophil counts, as no significant differences were found in lymphocyte counts between groups. Comparisons among participants with and without SI/SB and depression revealed similar trends with increased NLR, monocyte-to-lymphocyte ratio (MLR), and platelet-to-lymphocyte ratio (PLR) observed in depressed individuals with SI/SB compared to those without SI/SB. Broad alteration in the peripheral immune cell populations and their ratios were observed in individuals with SI/SB, indicating an immune activation or dysfunction. Notably, these immunological changes were also evident when comparing MDE individuals with and without SI/SB, suggesting that such immune dysfunction associated with suicidality cannot be solely attributed to or explained by depressive symptoms. The NLR, MLR, and PLR ratios, in combination with novel immune cellular and protein biomarkers, open new avenues in understanding the immunological underpinnings of SI/SB. These findings highlight the potential utility of immune markers as part of a multi-modal approach for risk stratification and therapeutic monitoring in SI/SB.

Association Between Mood Disorder Severity, Treatment Response and Systemic Inflammatory Markers: Exploring the Role of NLR, PLR, MLR, and SII

Background

In this study, the relationship between treatment response, clinical features of episodes such as psychosis, suicidal behavior, and agitation, duration of hospitalization, and systemic inflammation markers Systemic Inflammatory Index (SII), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and monocyte-to-lymphocyte ratio (MLR) in bipolar affective disorder manic episode (BAD-M), bipolar affective disorder-depressive episode (BAD-D), and major depressive disorder (MDD) were investigated.

Methods

TheNLR, MLR, PLR, and log SII were measured using parameters from a complete blood count. Admission and discharge Young Mania Rating Scale and Hamilton Depression Rating Scale scores were evaluated. This is a retrospective study conducted with a total of 451 inpatients, 122 (27.10%) of whom were diagnosed with BAD-M, 60 (13.20%) with BAD-D, and 269 (56.60%) with MDD.

Results

The patients with manic episodes have higher levels of NLR (P = .019), MLR (P = .002), and log SII (P = .007). In the bipolar depression and mania groups, the patients with and without treatment responses did not differ in terms of inflammation markers; the log PLR value was found to be higher in the unipolar depression group in the patients who did not reach remission (P = .048).

Conclusion

This study reveals associations between inflammation markers and different types of mood episodes. Higher NLR, MLR, and log SII levels in bipolar mania and lower NLR levels in agitated unipolar depression provide clues about changes in inflammation across different episodes. Studies with larger samples are needed to evaluate the relationship between inflammatory markers, the severity of mania and depression, and the response to treatment.

Inflammation and nitro-oxidative stress in current suicidal attempts and current suicidal ideation: a systematic review and meta-analysis

A meta-analysis showed a significant association between activated immune-inflammatory and nitro-oxidative (IO&NS) pathways and suicide attempts (SA). There is no data on whether recent suicidal ideation (SI) is accompanied by activated IO&NS pathways and whether there are differences between recent SA and SI. The current study searched PubMed, Google Scholar, and Web of Science, for articles published from inception until May 10, 2021, and systematically reviewed and meta-analysed the association between recent SA/SI (<3 months) and IO&NS biomarkers. We included studies which compared psychiatric patients with and without SA and SI and controls (either healthy controls or patients without SA/SI) and used meta-analysis (random-effect model with restricted maximum-likelihood) to delineate effect sizes with 95% confidence intervals (CI). Our search included 59 studies comprising 4.034 SA/SI cases and 12.377 controls. Patients with SA/SI showed activated IO&NS pathways (SMD: 0.299; CI: 0.200; 0.397) when compared to controls. The immune profiles were more strongly associated with SA than with SI, particularly when compared to healthy controls, as evidenced by activated IO&NS (SMD: 0.796; CI: 0.503; 1.089), immune (SMD: 1.409; CI: 0.637; 1.462), inflammatory (SMD: 1.200; CI: 0.584; 1.816), and neurotoxic (SMD: 0.904; CI: 0.431; 1.378) pathways. The effects sizes of the IO&NS, immune and inflammatory profiles were significantly greater in SA than in SI. In conclusion: activated IO&NS pathways are associated with recent SA and SI, and inflammation, T helper-1 activation, nitro-oxidative stress, lowered neuroprotection, and increased neurotoxicity explain at least in part why psychiatric patients show increased suicidal behaviours, especially SA.

Neutrophil/lymphocyte, platelet/lymphocyte and monocyte/lymphocyte ratios in mood disorders

Major depressive disorder (MDD) and bipolar disorders (BDs), the most severe types of mood disorders (MDs), are considered as among the most disabling illnesses worldwide. Several studies suggested that inflammatory neuroinflammation might be involved in the pathophysiology of MDs, while reporting increasing data on the relationships between these processes and classical neurotransmitters, hypothalamus-pituitary-adrenal axis (HPA), and neurotrophic factors. The assessment of neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR) and monocyte/lymphocyte ratio (MLR) in peripheral blood represents a simple method to evaluate the inflammatory status. The aim of the present paper was to review the literature on the possible relationships between NLR, PLR and MLR in MDs, and to comment on their possible wider use in clinical research. Thirty-five studies were included in the present review. The majority of them higher values of these parameters, particularly NLR values, in patients with MDs, when compared to healthy subjects. The increase would appear more robust in patients with BD during a manic episode, thus indicating that it could be considered as both state and trait markers. In addition, increased NLR and PLR levels seem to represent prognostic elements for the early discovery of post-stroke depression. The findings of the present review would indicate the need to carry our further studies in this field. In particular, NLR, PLR and MLR seem to be promising tools to detect economically and easily the activation of the inflammatory system, and to perhaps evaluate the etiology and course of MDs. Again, they could suggest some information to better understand the relationship between inflammatory and cardiovascular disease and MDs, and thus, to provide clinical implications in terms of management and treatment.

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

BACKGROUND

Precise identification of risk factors for suicide has been found as fundamentally challenging for the stakeholders. In search of that, the determination of potential biological markers of suicide has been scrutinizing in recent days. However, replicative studies across the culture and time are warranted to utilize the biomarkers in decision-making while considering suicide prevention.

OBJECTIVES

We aimed to measure the neutrophil-to-lymphocyte ratio (NLR) and C-reactive protein (CRP) in non-fatal suicidal attempts.

METHODS

This cross-sectional study was conducted from August 2020 to May 2021. Data were collected from 26 hospitalized patients after an immediate non-fatal suicidal attempt. We collected blood samples and assessed the complete blood count, NLR, and CRP. Data were analyzed by Statistical Package for the Social Science version 24.0 and Microsoft Excel software. We performed the independent Mann-Whitney U test to determine the variations between the groups. A value <.05 was considered as the level of significance.

RESULTS

The mean age of the study population was 24.1 (±7.3), more than half of them (n = 19, 73.1%) were female. The mode of attempt was either hanging (n = 13, 50.0%) or poisoning (n = 13, 50.0%). The previous attempt was noted in 12 (46.2%) cases. The mean CRP level was 16.8 (±30.2) mg/L and the mean NLR level was 8.3 (±6.8) for the total sample. Both the CRP and NLR were significantly higher among those who attempted hanging (P = .019 and .001).

CONCLUSIONS

The current study revealed preliminary findings on CRP and NLR among non-fatal suicides in Bangladesh where both of the parameters were significantly higher in non-fatal hanging.

Unique characteristics that distinguish suicide attempters from patients with nonsuicidal self-injury admitted to the emergency department following self-harm behavior: Psychological scales and biochemical markers

OBJECTIVE

The objective was to investigate the characteristics of suicide attempters as distinguished from nonsuicidal self-injury (NSSI) among those who are admitted to the emergency department (ED) following self-harm behavior using psychological scales and biochemical markers.

MATERIALS AND METHODS

The initial assessment forms and medical records of patients referred to the ED after self-harm behavior between March 2017 and December 2019 were retrospectively reviewed. Based on the patients' statements, two groups were formed: the NSSI group and the suicide attempt (SA) group.

RESULTS

This study included 578 patients, 76.6% (n = 443) in the SA group and 23.4% (n = 135) in the NSSI group. A univariate analysis comparing the SA and NSSI groups revealed that the SA group was statistically significantly associated with male sex, chronic disease, history of depression, unemployment, not seeking help after the attempt, reduced consciousness, and psychiatric consultation. Further, the SA group was older and showed higher Risk-Rescue Rating Scale (RRRS) value and white blood cell value compared to the NSSI group. However, multivariate logistic analysis did not produce statistically significant results for RRRS and any of the biological markers, with one exception for the accessibility to rescue item in the RRRS, where the NSSI group showed a statistically higher "ask for help" score compared to the SA group (P < 0.01).

CONCLUSIONS

Among patients who were admitted to the ED following self-harm behaviors, the risk factors for SA as opposed to NSSI were chronic disease and not seeking help after the attempt. In addition, suicide attempters tended to be more cooperative in psychiatric consultation following ED admission. In clinical practice, patients admitted due to NSSI should be administered treatment equivalent to that for suicide attempters if they exhibit the characteristics of suicide attempters.

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

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.