Association Between Peripheral Inflammatory and Hematological Markers and Suicide Attempts: A Retrospective Case–Control Study

Abstract

Objective

This study aimed to compare peripheral inflammatory markers between patients presenting after a suicide attempt and healthy controls, and to examine differences between first-time and multiple attempters.

Methods

This retrospective cross-sectional study included 90 patients presenting after a suicide attempt and 107 age- and sex-matched controls without psychiatric disorders between 2017 and 2024. Peripheral inflammatory indices, including neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), basophil-to-lymphocyte ratio (BLR), and neutrophil-to-albumin ratio (NAR), were calculated from complete blood count parameters. C-reactive protein (CRP) data were available only for the patient group. Group comparisons used the independent samples t-test or Mann–Whitney U test, and correlations were assessed with Spearman’s rho. Statistical significance was set at p<0.05.

Results

Compared with controls, patients with suicide attempts had significantly higher white blood cell, neutrophil, and monocyte counts, as well as higher inflammatory indices (NLR, MLR, NAR; all p<0.01), and lower albumin, hemoglobin, and hematocrit levels (all p<0.01). BLR was significantly higher in individuals with multiple suicide attempts compared to first-time attempters (p=0.023) and showed a weak positive correlation with the number of attempts (r=0.246, p=0.019). CRP, NLR, MLR, and NAR were positively correlated with the number of psychiatric hospitalizations. No significant sex-based differences were observed in inflammatory indices.

Conclusion

Peripheral inflammatory markers were altered in patients presenting after a suicide attempt. BLR showed a modest association with multiple suicide attempts. These findings are preliminary and should be confirmed in prospective studies.

INTRODUCTION

Suicidal behavior represents a major public health concern and a severe, potentially life-threatening outcome closely associated with psychiatric disorders [1,2]. According to the World Health Organization, approximately 700,000 individuals die by suicide each year, while the number of suicide attempts is substantially higher, underscoring the epidemiological importance of this phenomenon [3]. Among the most robust and consistent predictors of future suicide risk is a history of previous suicide attempts [2]. Individuals with a prior suicide attempt have been reported to have an approximately 4.8-fold higher risk of reattempting suicide during follow-up compared with those without such a history [4]. Repeated suicide attempts are also clinically important because they not only increase the likelihood of fatal outcomes but may also indicate a greater underlying biological vulnerability, or diathesis [5,6].

Suicidal behavior arises from a complex interplay of psychological, social, and biological factors [5]. In routine clinical practice, suicide risk assessment still relies largely on self-report and clinical observation, approaches that may fail to identify high-risk individuals, particularly those who conceal suicidal intent or engage in impulsive attempts with limited prior disclosure [6]. Although psychosocial factors remain central to assessment, individual vulnerability is also shaped by neurobiological mechanisms, some of which may be objectively measurable and clinically relevant [7]. In this context, peripheral inflammatory processes have attracted increasing interest, with elevated serum levels of C-reactive protein (CRP), tumor necrosis factor-alpha, and interleukin-6 reported in association with suicidal behavior [6,8]. These immune changes may influence central nervous system activity and stress regulation through serotonergic signaling, hypothalamic-pituitary-adrenal axis function, and microglial activation [9,10]. However, the extent and nature of the association between inflammatory alterations and suicidal behavior remain unclear, particularly whether these changes reflect suicidal behavior itself or the broader underlying clinical condition [11].

Importantly, recent work in psychiatric research highlights the value of investigating immune and metabolic dysregulation from a transdiagnostic and dimensional perspective [12,13]. Rather than viewing peripheral inflammation as a marker unique to specific categorical diagnoses, mounting evidence suggests that low-grade systemic inflammation spans across various mood and psychotic disorders, correlating more closely with clinical dimensions such as symptom severity, cognitive deficits, and cumulative chronic distress [12,13]. Given the practical limitations of routine serum cytokine measurement, interest has shifted toward inexpensive and accessible complete blood count (CBC)-derived inflammatory indices, including the neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), basophil-to-lymphocyte ratio (BLR), neutrophil-to-albumin ratio (NAR), and platelet-to-lymphocyte ratio (PLR), which have been increasingly investigated as practical markers of inflammation in psychiatric disorders and suicidal behavior [10,11,14-16].

The primary aim of this study is to compare peripheral inflammatory and hematological markers between individuals presenting with a suicide attempt and healthy controls, and to investigate differences between first-time and multiple attempters. By focusing on these groups, the study seeks to explore peripheral inflammatory changes associated with acute suicidal behavior, with the goal of contributing to hypothesis generation regarding biological correlates of suicide risk in clinical settings.

METHODS

Study design and participants

This retrospective, cross-sectional, case-control study was conducted at a single tertiary care center. Medical records of patients who presented to the Adult Emergency Department of Trabzon Fatih State Hospital between January 2017 and December 2024 and were referred for psychiatric evaluation were reviewed. All personal health data were anonymized prior to analysis. The study protocol was approved by the Ethics Committee of Sivas Cumhuriyet University Health Sciences Research (Decision No: 2025-05/61, dated 15 May 2025) and was conducted in accordance with the Declaration of Helsinki. Given the retrospective design of the study, the requirement for informed consent was waived.

The study group included individuals aged 17 to 65 years who presented to the emergency department following a suicide attempt and were evaluated by a psychiatrist. The control group consisted of age- and sex-matched individuals who underwent assessment as part of the hospital’s health board evaluation process for administrative or occupational purposes. Control participants were evaluated by board-certified psychiatrists according to DSM-5 criteria. The absence of psychiatric disorders, current psychiatric symptoms, psychotropic medication use, and lifetime suicidal behavior was confirmed. In addition, hospital records were reviewed to verify that no psychiatric diagnosis or treatment had been documented within the preceding six months.

Participants in both groups were excluded if they had conditions that could affect inflammatory parameters, including acute infection at presentation, chronic inflammatory or autoimmune disease, malignancy, significant neurological disorder, or recent use of systemic corticosteroids or immunomodulatory agents.

Procedure

Data collection was performed through retrospective review of hospital information systems and electronic laboratory databases. A standardized data extraction form was used to collect sociodemographic variables, including age, sex, and marital status, as well as clinical variables such as suicide attempt history, categorized as first or multiple attempts, method of attempt, primary psychiatric diagnosis according to DSM-5 criteria, comorbid psychiatric conditions, number of previous psychiatric hospitalizations, family history of suicide, and presence of medical comorbidities. For the control group, hospital records were reviewed to confirm the absence of psychiatric diagnoses, suicide attempts, and psychiatric treatment within the preceding six months.

Laboratory measurements

Laboratory data were retrieved from electronic records corresponding to the index emergency department admission and obtained prior to any medical or psychiatric intervention. Recorded parameters included CRP, albumin, white blood cell count (WBC), red blood cell count (RBC), hemoglobin (HGB), hematocrit (HCT), neutrophil count, lymphocyte count, monocyte count, basophil count, and eosinophil count. Peripheral inflammatory indices were calculated as follows: NLR, MLR, BLR, and NAR. CRP measurements were not available for all participants and were therefore analyzed only within the suicide attempt group; the extent of missing data is reported in the relevant tables.

Statistical analysis

Statistical analyses were conducted using IBM SPSS Statistics (version 26.0; IBM Corp.). Categorical variables were presented as frequencies and percentages, while continuous variables were expressed as mean±standard deviation for normally distributed data and median with interquartile range for nonnormally distributed data. The normality of continuous variables was assessed using the Shapiro–Wilk test, supplemented by evaluation of skewness and kurtosis values (acceptable range: -1.5 to +1.5).

Group comparisons were performed using independent samples t-test for normally distributed variables and Mann–Whitney U test for non-normally distributed variables. Categorical variables were analyzed using Pearson’s chi-square test. Associations between inflammatory markers and clinical variables were evaluated using Spearman’s rank correlation coefficient. Receiver operating characteristic (ROC) curve analysis was performed to assess the ability of inflammatory markers to differentiate between first-time and multiple suicide attempts, and area under the curve (AUC) values with 95% confidence intervals (CIs) were calculated. Sensitivity, specificity, and optimal cutoff values were determined where applicable.

All analyses were conducted using available data, and missing values were reported in the corresponding tables. A p-value of less than 0.05 was considered statistically significant. Given the exploratory nature of the study, no formal correction for multiple comparisons was applied.

RESULTS

Sociodemographic and clinical characteristics

A total of 197 participants were included in the study, including 90 individuals in the suicide attempt group and 107 individuals in the control group. There were no statistically significant differences between the groups in terms of age, sex, or marital status (all p>0.05) (Table 1). Among individuals in the suicide attempt group, drug ingestion was the most common method of suicide attempt, accounting for 90.0% of cases. Most patients (64.4%) presented after a first suicide attempt, while 35.6% had multiple suicide attempts. Among overdose cases, psychotropic medications, especially antidepressants and antidepressant-based combinations, were the most frequently involved substances.

Table 1.

Sociodemographic and clinical characteristics of the study participants

Variables	Suicide group (N=90)	Control group (N=107)	p
Sex			0.065
Female	59 (65.6)	56 (52.3)
Male	31 (34.4)	51 (47.7)
Age (yr)	31.61±10.06	30.70±9.97	0.539
Marital status			0.318
Married	29 (32.2)	42 (39.3)
Single	61 (67.8)	65 (60.7)
Number of psychiatric hospitalizations	0.90±2.24	-	-
Method of suicide attempt		-	-
Drug ingestion	81 (90.0)
Cutting/self-injury	4 (4.4)
Hanging	2 (2.2)
Poisoning with chemicals	2 (2.2)
Jumping from height	1 (1.1)
Number of suicide attempts
First attempt	58 (64.4)	-	-
Multiple attempts	32 (35.6)	-	-
Family history of suicide	10 (11.1)	-	-
Types of drugs used in suicide attempts (N=81)
Psychotropic drugs	65 (80.3)	-	-
Non-psychotropic drugs	14 (17.3)	-	-
Combination of psychotropic and non-psychotropic drugs	2 (2.5)	-	-

Values are presented as mean±standard deviation or N (%). Group differences in categorical variables, including sex and marital status, were assessed using the chi-square test, while differences in the continuous variable age were examined with the independent samples t-test. A pvalue of <0.05 was considered statistically significant.

Psychiatric diagnoses and biomarker comparisons

The most frequent primary psychiatric diagnoses in the suicide attempt group were depressive disorders (23.3%), followed by adjustment- or trauma-related disorders (18.9%), anxiety disorders (17.8%), and disruptive or impulse-control disorders (17.8%). Comorbid cluster B personality disorders were identified in 24.4% of patients.

Compared with the control group, individuals in the suicide attempt group had significantly lower albumin, RBC count, HGB, and HCT levels (all p<0.01) (Table 2). In contrast, WBC count, neutrophil, monocyte, and basophil counts, neutrophil percentage, and inflammatory indices including NLR, MLR, NAR, and BLR were significantly higher in the suicide attempt group (all p<0.01) (Table 2). No statistically significant between-group differences were found for lymphocyte or eosinophil counts (both p>0.05).

Table 2.

Comparison of hematological and inflammatory biomarkers between study groups and subgroup analyses based on comorbid psychiatric diagnosis and sex

Parameter	Patient group (N=90)	Control group (N=107)	p	With comorbid diagnosis (N=22)	Without comorbid diagnosis (N=68)	p	Females (N=59)	Males (N=31)	p
Albumin (g/dL)	4.08±0.51	4.44±0.42	<0.001**	4.08±0.47	4.08±0.52	0.998	4.10±0.49	4.04±0.55	0.546
WBC (10³/µL)	8.86±2.50	7.10±1.43	0.001**	8.95±2.10	8.83±2.61	0.832	8.64±2.31	9.28±2.78	0.292
RBC (10⁶/µL)	4.41±0.50	4.81±0.53	0.005**	4.45±0.55	4.40±0.48	0.648	4.21±0.32	4.79±0.51	<0.001**
Hemoglobin (g/dL)	13.26±1.75	14.87±4.23	0.002**	13.40±1.80	13.21±1.73	0.662	12.45±1.25	14.80±1.48	<0.001**
Hematocrit (%)	39.74±4.59	43.25±4.56	0.009**	40.20±4.96	39.59±4.47	0.585	37.52±2.96	43.97±4.29	<0.001**
Neutrophil (10³/µL)	5.67±2.34	4.13±1.10	<0.001**	5.61±2.27	5.69±2.36	0.891	5.60±2.44	5.80±2.15	0.732
Monocytes (10³/µL)	0.62±0.25	0.48±0.13	<0.001**	0.62±0.26	0.62±0.25	0.999	0.58±0.20	0.70±0.31	0.055
Basophils (10³/µL)	0.06±0.04	0.04±0.10	0.003**	0.06±0.05	0.06±0.04	0.999	0.06±0.05	0.06±0.04	0.999
% Neutrophil	62.62±12.59	57.72±7.30	<0.001**	61.61±14.53	62.95±11.92	0.678	63.19±12.29	61.54±13.11	0.560
BLR	0.026±0.019	0.016±0.010	0.001**	0.029±0.020	0.025±0.018	0.385	0.025±0.019	0.028±0.018	0.463
NAR	1.39±0.59	0.93±0.25	<0.001**	1.36±0.46	1.40±0.63	0.784	1.37±0.58	1.43±0.61	0.645
NLR	3.33±3.22	1.89±0.75	<0.001**	3.41±3.52	3.30±3.12	0.892	3.29±3.01	3.41±3.61	0.868
MLR	0.31±0.20	0.22±0.08	<0.001**	0.31±0.18	0.31±0.20	0.999	0.30±0.14	0.33±0.27	0.495
Lymphocytes (10³/µL)	2.33±1.07	2.31±1.10	0.197	2.30±1.16	2.34±1.04	0.879	2.25±0.97	2.48±1.22	0.324
Eosinophils	0.17±0.15	0.14±0.10	0.628	0.16±0.10	0.17±0.16	0.789	0.15±0.15	0.21±0.15	0.076

Values are presented as mean±standard deviation.

^**p<0.01.

WBC, white blood cell; RBC, red blood cell; NLR, neutrophil-to-lymphocyte ratio; MLR, monocyte-to-lymphocyte ratio; BLR, basophil-to-lymphocyte ratio; NAR, neutrophil-to-albumin ratio.

Because CRP data were not available for the control group, between-group comparisons could not be performed for CRP. Within the suicide attempt group, inflammatory markers including CRP, NLR, MLR, NAR, and BLR did not differ significantly according to the presence of comorbid psychiatric disorders or sex (all p>0.05). A detailed summary of biomarker comparisons is presented in Table 2.

Biomarkers according to suicide attempt history

When patients were stratified according to suicide attempt history, BLR was significantly higher in individuals with multiple suicide attempts than in those with a first attempt (p=0.023) (Table 3). No significant differences were observed between first-time and multiple attempters in terms of NLR, MLR, NAR, or CRP levels (all p>0.05) (Table 3).

Table 3.

Comparison of inflammatory biomarkers according to the number of suicide attempts

Parameter	First attempt (N=58)	Multiple attempts (N=32)	p
NLR	3.11±2.81	3.71±3.85	0.866
MLR	0.32±0.20	0.29±0.17	0.436
NAR	1.38±0.55	1.45±0.65	0.600
BLR	0.02±0.01	0.03±0.01	0.023*
CRP (mg/L)	3.15 (2.0–10.9)	3.60 (2.0–9.0)	0.914

Values are presented as mean±standard deviation or median (interquartile range). Normality was assessed using the Shapiro–Wilk test. Group comparisons for NLR, MLR, NAR, and BLR were performed using the independent samples t-test. CRP was compared using the Mann–Whitney U test.

^*p<0.05.

NLR, neutrophil-tolymphocyte ratio; MLR, monocyte-to-lymphocyte ratio; BLR, basophil-to-lymphocyte ratio; NAR, neutrophil-to-albumin ratio; CRP, C-reactive protein.

Logistic regression analysis

A binary logistic regression analysis was performed to evaluate whether BLR independently predicted multiple suicide attempts after adjustment for age and sex. In this model, log-transformed BLR did not independently predict multiple suicide attempts (odds ratio=1.38, 95% CI: 0.60–3.20, p=0.453) (Table 4). Age and sex were also not significant independent predictors of multiple suicide attempts (both p>0.05) (Table 4).

Table 4.

Logistic regression analysis using log-transformed BLR

Variable	OR	95% CI	p
Log-transformed BLR	1.38	0.60–3.20	0.453
Age	1.03	0.97–1.09	0.346
Sex (male)	1.57	0.47–5.26	0.463

Binary logistic regression analysis was performed using the enter method to evaluate potential independent predictors of multiple suicide attempts (defined as ≥2 lifetime attempts) within the patient group. Due to a severely skewed distribution, baseline BLR values underwent log transformation prior to multivariable entry to satisfy regression assumptions. Age and sex were forced into the multivariable model as primary demographic covariates. Statistical significance was defined as p<0.05. OR, odds ratio; CI, confidence interval; BLR, basophil-to-lymphocyte ratio.

Correlation analyses and ROC findings

Correlation analyses showed a weak but statistically significant positive association between BLR and the number of suicide attempts (r=0.246, p=0.019) (Table 5). In addition, CRP, NLR, MLR, and NAR were positively correlated with the number of previous psychiatric hospitalizations (r=0.258–0.404, all p<0.05) (Table 5). A strong positive correlation was found between NAR and NLR (r=0.759, p<0.001), while a moderate positive correlation was observed between NAR and MLR (r=0.423, p<0.001) (Table 5).

Table 5.

Correlations between inflammatory markers and clinical variables

Variable 1	Variable 2	r	p
CRP	Number of psychiatric hospitalizations	0.404	<0.001**
NLR	Number of psychiatric hospitalizations	0.277	0.007**
MLR	Number of psychiatric hospitalizations	0.258	0.011*
NAR	Number of psychiatric hospitalizations	0.313	0.002**
BLR	Number of suicide attempts	0.246	0.019*
NAR	NLR	0.759	<0.001**
NAR	MLR	0.423	<0.001**

Correlation analyses were conducted using Spearman correlation coefficients.

^*p<0.05;

^**p<0.01.

CRP, C-reactive protein; NLR, neutrophilto-lymphocyte ratio; MLR, monocyte-to-lymphocyte ratio; BLR, basophil-to-lymphocyte ratio; NAR, neutrophil-to-albumin ratio.

ROC analysis showed that BLR had the highest, although limited, discriminative ability for distinguishing individuals with multiple suicide attempts from those with a first attempt (AUC=0.645). In contrast, CRP, NLR, and MLR showed poor discriminative performance, with AUC values close to 0.50. ROC curves are presented in Figure 1.

Figure 1.

ROC curves of peripheral inflammatory markers in differentiating first vs. multiple suicide attempts. ROC, receiver operating characteristic; CRP, C-reactive protein; NLR, neutrophilto- lymphocyte ratio; MLR, monocyte-to-lymphocyte ratio; BLR, basophil-to-lymphocyte ratio; AUC, area under the curve.

DISCUSSION

The present study compared peripheral inflammatory and hematological markers between patients presenting after a suicide attempt and healthy controls. NLR, MLR, NAR, and BLR were higher in the suicide attempt group, whereas albumin, RBC count, HGB, and HCT were lower. BLR was higher in patients with multiple attempts and was weakly correlated with the number of attempts, while CRP, NLR, MLR, and NAR were positively correlated with previous psychiatric hospitalizations. No significant differences were observed according to sex or comorbid psychiatric disorders. Overall, these findings support an association between peripheral inflammatory alterations and suicidal behavior, although the observed effects were modest. Because of the retrospective and cross-sectional design of this study these findings should be interpreted as associations rather than evidence supporting a direct causal role of inflammation in suicidal behavior.

Our findings are broadly consistent with the growing literature linking suicidal behavior to peripheral inflammatory activation [17-19]. Compared with healthy controls, individuals presenting after a suicide attempt showed higher WBC, neutrophil, monocyte, and basophil counts, along with higher NLR, MLR, NAR, and BLR values. Among these markers, NLR has emerged as one of the most consistently reported inflammatory parameters associated with suicidal behavior, with elevated levels also observed in individuals engaging in violent suicide attempts. However, its specificity as a standalone marker of suicide risk remains limited [18,20,21]. The overall pattern observed in our study may indicate a shift toward innate immune activation and relative immune imbalance, although this interpretation should remain cautious.

The elevated BLR among multiple attempters introduces an interesting biological consideration. Historically, basophils have been viewed primarily as mediators of type I hypersensitivity and allergic responses. However, contemporary immunobiology recognizes basophils as modulators of both innate and adaptive immune responses, partly through the release of histamine, leukotrienes, and pro-inflammatory cytokines, including interleukins [22]. These mediators may contribute to broader immune signaling pathways that can influence neuroimmune processes, including blood-brain barrier regulation and low-grade neuroinflammatory activity [23]. Inflammatory signaling has also been linked to changes in monoaminergic neurotransmission and stress-related behavioral responses [24]. Furthermore, systemic or chronic emotional stress may activate the hypothalamic-pituitary-adrenal axis and interact with immune cell activity, potentially influencing peripheral inflammatory indices [25]. Nevertheless, this interpretation should be regarded as speculative. In the present study, BLR did not remain an independent predictor of multiple suicide attempts after adjustment for age and sex, and its ROC performance was limited. Therefore, BLR should not be considered a standalone clinical biomarker; rather, the observed association should be interpreted as preliminary and hypothesis-generating.

Another possible interpretation is that the elevated BLR observed in multiple attempters may reflect higher underlying stress vulnerability, impulsivity, or cumulative physiological strain rather than a suicide-specific biological mechanism [5,6]. This interpretation is consistent with the modest discriminative performance of BLR in ROC analysis and with the finding that log-transformed BLR was not an independent predictor after adjustment for age and sex. Therefore, although BLR may be of interest as an exploratory marker, the present findings do not support its use as a standalone clinical tool for predicting recurrent suicidal behavior.

In our study, the suicide attempt group also showed lower albumin, RBC count, HGB, and HCT levels than healthy controls. This pattern may be relevant in light of previous literature suggesting that these parameters reflect not only inflammatory activity but also broader physiological stress and impaired systemic resilience in suicidal behavior. Albumin, as a negative acute-phase reactant, may decrease in the context of systemic inflammation, whereas lower RBC-related parameters may indicate reduced oxygen-carrying capacity, nutritional burden, or other chronic stress-related physiological changes [26,27]. Prior studies have likewise reported lower albumin, HGB, and HCT levels in individuals with suicidal behavior, although findings for RBC-related measures have not been entirely uniform across populations [26-28].

A recent study with a similar design reported that NLR, MLR, BLR, systemic immune-inflammation index, platelet distribution width, and NAR values were higher in patients with suicide attempts than in healthy controls, and that BLR, systemic immune-inflammation index, and NAR were particularly elevated in individuals with more than one suicide attempt [19]. This finding is consistent with our observation that BLR differentiated multiple suicide attempts from first attempts and was weakly but significantly correlated with the number of attempts.

In contrast, CRP levels were not associated with multiple suicide attempts but showed a positive correlation with the number of previous psychiatric hospitalizations. This pattern suggests that CRP may be more closely related to overall clinical burden or illness chronicity than to multiple suicide attempts specifically. This interpretation is consistent with previous studies reporting higher CRP levels in individuals with suicidality and with broader literature suggesting an association between inflammatory markers and illness burden in depressive disorders [13,28,29]. However, because CRP data were not available for the control group, case-control comparisons could not be performed, and CRP-related findings should therefore be interpreted with caution.

From a clinical perspective, readily accessible peripheral inflammatory markers, including NLR, MLR, NAR, and BLR, may provide supplementary information in the evaluation of suicidal behavior. However, given their modest effect sizes, limited discriminative capacity, and lack of independent predictive value, these biomarkers should be interpreted cautiously and only as part of a broader clinical assessment.

Several limitations must be carefully weighed when interpreting these results. First, causality cannot be inferred due to the retrospective, cross-sectional design of the study. Second, the absence of CRP data in the healthy control group prevented case-control comparisons for this marker and restricted conclusions regarding CRP. Third, the relatively small sample size, especially in subgroup analyses, may have reduced statistical power. Fourth, residual confounding from unmeasured or unrecorded variables remains possible. Because of the retrospective design, we were unable to systematically control for potential confounding influences such as smoking status, body mass index, nutritional status, specific medication exposure, socioeconomic variables, and unrecognized medical conditions, all of which may affect circulating WBC lineages and inflammatory profiles. Fifth, biomarker levels were assessed at a single time point, which may not adequately capture the dynamic nature of inflammatory processes.

Finally, an additional limitation is that most suicide attempts in the present sample involved acute drug ingestion. Acute physiological responses related to overdose, including transient inflammatory, metabolic, or hematological changes, may have influenced laboratory findings obtained at emergency admission. Therefore, the observed changes in complete blood count-derived indices may partially reflect overdose-related physiological effects rather than inflammatory alterations associated with suicidal behavior itself. Moreover, the predominance of overdose attempts may limit the generalizability of the findings to individuals using other methods of self-harm.

Despite these limitations, the study has several strengths. A broad range of hematological and inflammatory markers was evaluated within the same cohort, providing a comprehensive biological profile. The inclusion of a demographically matched control group without psychiatric disorders enhances the validity of the comparisons. Furthermore, the use of objective clinical and laboratory data derived from hospital records increases data reliability. The integration of clinical and biological variables allows for a more comprehensive evaluation of suicidal behavior.

In conclusion, this study suggests that peripheral inflammatory and hematological markers are altered in individuals presenting after a suicide attempt. Although BLR was associated with multiple suicide attempts in univariate analyses, it did not emerge as an independent predictor after adjustment for age and sex. Therefore, this finding should be considered preliminary and hypothesis-generating rather than evidence supporting the clinical utility of BLR as a standalone predictive biomarker. Further prospective and longitudinal studies are required to clarify the clinical relevance and underlying mechanisms of these associations.