Inflammatory Biomarkers in Acute Suicidal Behaviors

This review focuses on suicidal ideation and attempts in the context of major depressive disorder. Despite clinical advances, suicide risk assessment still relies mainly on subjective evaluation. Emerging evidence highlights immune-inflammatory dysregulation as a biological link between depression and suicidality. This review summarizes current findings on inflammatory biomarkers as potential predictors of suicidal behavior. The discussed markers include acute phase proteins (C-reactive protein, homocysteine), hematological indices from routine blood tests (NLR, PLR, MLR, SII, NAR), and cytokines (IL-6, TNF-α, IL-1β, IL-4, IL-10). Many studies report increased levels of CRP, IL-6, TNF-α, and IL-1β and decreased IL-4 and IL-10 in suicidal individuals, reflecting an imbalance between the immune-inflammatory response system (IRS) and the compensatory immune-regulatory reflex system (CIRS). Such dysregulation may promote neuroinflammation and neurotoxicity via the kynurenine pathway. Hematological ratios offer inexpensive, accessible indicators that could complement psychiatric evaluation. However, heterogeneity across studies, lack of standardized cut-off values, and the influence of confounders such as age, sex, and medication limit their clinical utility. Inflammatory biomarkers currently hold potential as objective adjuncts-but not substitutes-to clinical judgment in assessing suicide risk.