Inflammatory Parameters in Patients with Suicide Attempts by Drug Overdose: A Comparative Study with a Comparison Group

Background and Objectives: The relationship between psychiatric disorders and systemic inflammation remains incompletely understood. Increasing evidence suggests that inflammatory processes may play a role in the biological mechanisms underlying suicidal behavior. This study aimed to investigate the association between classical inflammatory markers and hemogram-derived inflammatory indices in patients who attempted suicide by oral drug overdose. Materials and Methods: This retrospective observational comparative study included 343 patients hospitalized following a suicide attempt by oral medication overdose and 421 age- and sex-matched healthy individuals. Serum C-reactive protein (CRP), albumin levels, complete blood count parameters, and derived inflammatory indices, including the CRP-to-albumin ratio (CAR), neutrophil-to-lymphocyte ratio (NLR), systemic immune–inflammation index (SIII), platelet-to-lymphocyte ratio (PLR), and monocyte-to-lymphocyte ratio (MLR), were analyzed. Results: Patients with suicide attempts had significantly higher CRP, leukocyte, neutrophil, and monocyte levels compared to the comparison group. CAR, NLR, SIII, and MLR values were also significantly elevated, whereas PLR did not differ between groups. ROC analysis demonstrated that CAR showed the highest discriminative ability for suicide attempt, with high sensitivity and specificity. Conclusions: Hemogram-derived inflammatory indices, particularly CAR, were significantly associated with suicide attempts. These easily accessible and low-cost biomarkers may provide additional biological insight into suicide risk assessment. Further prospective studies are needed to confirm these findings.