Accumulating research has suggested a possible role of the immune/inflammatory response system in the pathophysiology of suicidal behavior, more specifically of specifically high-lethality suicide attempts (SA). To count with reliable and affordable biological markers of high-lethality SA to complement clinical assessment for early detection of individuals at a high risk of committing suicide is thus mandatory.

To assess if immune/inflammatory parameters may differ between suicide attempters with and without SA, taking into account the type of suicide method. The odds of repeating a high-lethality SA in the future will also be explored.

In this retrospective observational single center study, medical records of suicide attempters admitted to the Emergency Department at Vall d’Hebron University Hospital (Barcelona, Spain) between 2017-2021, will be reviewed. The following immune/inflammatory parameters (i.e., total and differential white blood cell count, platelet counts, C-reactive protein levels) will be extracted for comparisons between subjects without a history of previous suicide attempt (SA), and those with a history of previous SA. Additionally, the following ratios/indexes will be calculated as a proxy of subject’s inflammatory status: neutrophil-to-lymphocyte ratio (NLR), basophil-to-lymphocyte-ratio (BLR), monocyte-to-lymphocyte ratio (MLR), platelet-to-lymphocyte ratio (PLR), systemic inflammatory response index (SIRI). Analyses will be controlled for clinical and sociodemographic variables, such as age, gender and/or primary psychiatric diagnosis. Analyses will be also stratified according to the attempt method. Moreover, the capability of the previously mentioned parameters to predict a high lethality SA or to commit suicide in the coming two years will also be evaluated.

Results from the interim analysis will be presented at the congress.

Peripheral immune/inflammatory parameters may allow us to discriminate subjects at risk of committing suicide. In case of positive findings, immune/inflammatory parameters could be incorporated in the comprehensive evaluation of high-lethality SA in individuals admitted to the emergency setting, contributing to improve early detection of suicide risk.

L. Martorell Mensua Shareolder of: First authorship, W. Vidal Cachay Shareolder of: First authorship, M. Quesada Franco: None Declared, A. Beneria Gonzalez: None Declared, J. Ramos Quiroga: None Declared, A. Motger Albertí: None Declared, G. Arteaga-Henriquez Shareolder of: Last authorship, D. Braquehais Conesa Shareolder of: Last authorship.