In recent years, the intricate links between psychological health and physiological markers have intensified scientific inquiry into potential biological correlates of mental disorders. One particularly distressing mental health condition—suicidality—has garnered significant attention, given its complex and multifactorial etiology. Inflammatory processes, traditionally associated with systemic diseases, are emerging as potential contributors to psychiatric symptoms and suicidal behavior. A novel study published in BMC Psychiatry offers an in-depth examination of inflammatory biomarkers, including C-reactive protein (CRP)/albumin and neutrophil/albumin ratios, to investigate their relationship with suicidality in a psychiatric inpatient population.
The research harnesses a retrospective cross-sectional design, focusing on female psychiatric inpatients aged 18 to 65 years within the Psychiatry Department of Goztepe Prof. Dr. Suleyman Yalcin City Hospital, spanning admissions from 2022 to 2024. The specificity of the sample—female inpatients—addresses an important gap, considering sex-based differences in inflammatory profiles and mental health disorders. Through detailed hematological assessments, the study evaluates classic inflammatory markers such as CRP, albumin, neutrophils, lymphocytes, monocytes, and platelets, alongside indices like red cell distribution width (RDW) and mean platelet volume (MPV).
Importantly, the study extends into derived inflammatory ratios, which have been increasingly considered for their diagnostic and prognostic potential in various diseases. Ratios examined include neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), platelet-to-lymphocyte ratio (PLR), alongside the computed CRP-to-albumin ratio (CAR) and neutrophil-to-albumin ratio (NAR). These composite markers are thought to reflect the balance between pro-inflammatory and anti-inflammatory forces, potentially mirroring systemic inflammation’s impact on brain function and behavior.
Interestingly, the comprehensive analysis revealed no statistically significant differences between the suicidality group—encompassing individuals with both suicidal ideation and a history of suicide attempts—and the non-suicidal cohort across all measured biomarkers and ratios. The parameters MPV, RDW, NLR, MLR, PLR, CAR, and NAR all demonstrated p-values exceeding the conventional threshold for significance (p > 0.05), suggesting limited or no association in this sample context.
These findings challenge some prevalent hypotheses proposing inflammation as a biomarker or mechanistic driver of suicidality. While prior studies have linked elevated inflammatory markers to suicidal behavior, the current research nuances this paradigm, emphasizing the need for cautious interpretation. Variability in patient populations, clinical settings, and methodological approaches may influence results—a reminder that the pathogenesis of suicidality resists reduction to simple biological correlates.
The lack of significant biomarker differences indicates that inflammation, at least as captured by these serum parameters, may not serve as a robust or standalone indicator for suicide risk among psychiatric inpatients. This has profound implications for clinical practice since biomarker-driven screening or intervention strategies require reliable and reproducible biological signals. The study suggests that relying solely on these inflammatory metrics could be inadequate for risk stratification or as a mechanistic proxy for suicidality.
However, the research team underscores the inherent limitations of their design, notably the retrospective cross-sectional approach and the relatively homogenous sample restricted to females within a single clinical setting. Inflammatory responses are known to be dynamic, influenced by age, sex, comorbidities, and psychotropic medications, any of which may confound findings. Therefore, the absence of observed differences might reflect sample-specific nuances or temporal variations not captured in cross-sectional snapshots.
Further, the study calls for larger-scale, prospective investigations involving more diverse populations to definitively elucidate the role of inflammatory pathways in suicidal behavior. Longitudinal assessments might unravel temporal relationships between biomarker fluctuations and the emergence or resolution of suicidality. Additionally, leveraging high-sensitivity assays, cytokine profiling, and integrating neuroimaging could provide a multidimensional understanding of the neuroimmune interface.
From a mechanistic standpoint, inflammation’s putative influence on brain regions implicated in mood regulation, decision-making, and impulse control—such as the prefrontal cortex and limbic system—remains a fertile area for exploration. Neuroinflammation could modulate neurotransmission, plasticity, and stress responses, potentially underpinning suicidal ideation and actions in susceptible individuals. Nevertheless, this study’s findings advocate for a measured view, positing that inflammation alone is insufficient as a diagnostic or predictive biomarker.
The research contributes significantly to psychiatric biomarker literature by refining the narrative around common systemic inflammation markers like CRP and blood cell ratios. Previous enthusiasm about inflammation markers as accessible, cost-effective tools must now contend with nuanced evidence that their utility may be context-dependent and not universally applicable across psychiatric diagnoses or symptom manifestations. This calls for integrative biomarker panels or composite models combining immunological signals with genetic, environmental, and clinical variables.
Clinicians and researchers are thus reminded of suicidality’s multifactorial nature, integrating psychological, environmental, genetic, and biological layers. Personalized assessment and comprehensive risk evaluation remain paramount in suicide prevention strategies. Meanwhile, biomarker research should continue, tailored by methodological rigor and attentiveness to patient heterogeneity.
In sum, while inflammation remains a compelling domain in psychiatry research, this study published in BMC Psychiatry tempers conclusions regarding CRP/albumin and neutrophil/albumin ratios as markers of suicidality. It urges the scientific community to pursue more expansive and methodologically robust studies, aspiring to unravel the complex biological substrates of one of mental health’s most urgent challenges.
Subject of Research: Relationship between suicidality and inflammatory biomarkers in psychiatric inpatients.
Article Title: Assessing the relationship between suicidality and inflammatory biomarkers: C-reactive protein/albumin and neutrophil/albumin ratios in an inpatient setting.
Article References:
Elbay, R.Y., Erdil, S.S. & İlhan, A.H. Assessing the relationship between suicidality and inflammatory biomarkers: C-reactive protein/albumin and neutrophil/albumin ratios in an inpatient setting. BMC Psychiatry 25, 947 (2025). https://doi.org/10.1186/s12888-025-07416-9
Image Credits: AI Generated
