BRIEF RESEARCH REPORT article
Front. Psychiatry
Sec. Mood Disorders
This article is part of the Research TopicPrevention-Oriented Suicide Risk AssessmentView all 7 articles
Elevated monocyte-to-lymphocyte ratio, C-reactive protein and further inflammatory parameters as potential biomarkers of suicide risk in bipolar I disorder
Provisionally accepted
Borbála Pethő1*
Robert Herold1
Diana Simon2
Márton Áron Kovács1
Tünde Tóth3
Noémi Albert1
Dora Hebling1
András Sándor Hajnal1
Timea Csulak1
Marton Herold1
Tamás Tényi1- 1Department of Psychiatry and Psychotherapy, Medical School, University of Pécs, Pécs, Hungary
- 2Department of Immunology and Biotechnology, Clinical Center, University of Pécs, Pécs, Hungary
- 3Department of Anatomy, Medical School, University of Pécs, Pécs, Hungary
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Suicide is an unresolved issue in psychiatry to this day. Suicide risk (SR) is particularly high for psychiatric patients with bipolar I disorder (BD). Recent studies suggest an immunological dysregulation in the background. In our retrospective study, we investigated laboratory parameters of BD in-patients (n = 116) between January 2020 and June 2024. Data was collected regarding the following parameters: white blood cell, neutrophil, lymphocyte, monocyte and platelet count, monocyte-to-lymphocyte (MLR), neutrophil-to-lymphocyte (NLR) and platelet-to-lymphocyte ratio (PLR), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), red blood cell distribution width (RDW) and mean platelet volume (MPV). Individuals with recent (≤ 48 hours prior) suicide attempt (SA) (n = 21) and with past (> 48 hours prior) SA (n = 16) represented the high SR group (n = 37). BD patients with no history of SA composed the intermediate SR group (n = 79). We found a significant increase in MLR, monocyte count, CRP and ESR in patients with recent SA compared to those with no history of SA. Comparing high and intermediate SR patients, MLR, monocyte count, CRP and ESR remained elevated in the former group. As implied by previous research, immunological mechanisms may contribute to the emergence of suicidality. Investigating BD patients as the subgroup at significant risk, changes in certain inflammatory markers further strengthen the assumption of immunological processes in the background of suicidality, and these parameters may serve as potential future biomarkers of SR.
Keywords: biomarker, Inflammation, Laboratory parameters, Bipolar I disorder, Monocyte-to-lymphocyte ratio, Suicidality
Received: 16 Jun 2025; Accepted: 25 Nov 2025.
Copyright: © 2025 Pethő, Herold, Simon, Kovács, Tóth, Albert, Hebling, Hajnal, Csulak, Herold and Tényi. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Borbála Pethő
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