A comparative study of C-reactive protein levels in patients with major depressive disorder with and without suicidal attempts

Abstract

Introduction and aim. Major depressive disorder (MDD) is closely linked to suicidal behavior, and systemic inflammation ‒ particularly elevated C-reactive protein (CRP) ‒ has been proposed as a contributing factor. However, evidence comparing CRP patterns separately in suicide attempters and non-attempters remains limited, especially in underrepresented populations. The aim of this study was to compare serum CRP levels in patients with MDD with and without a history of suicide attempts. Material and methods. This cross-sectional analytical study included 60 adults diagnosed with MDD according to ICD-10 criteria. Participants were divided into two groups: those with a history of suicide attempts (n=30) and those without such a history (n=30). Depression severity was assessed using the Hamilton Depression Rating Scale (HAM-D). Serum CRP levels were measured using a turbidimetric method. Statistical analyses included Student’s t-test, Mann-Whitney U-test, and Pearson’s correlation. Results. CRP levels were significantly higher among suicide attempters compared with non-attempters (4.47±3.53 mg/L vs 2.50±3.59 mg/L; p=0.03). A significant positive correlation between HAM-D scores and CRP levels was observed in the suicide-attempt group (R=0.52; p=0.003), whereas no such correlation was found in non-attempters (R=0.12; p=0.52). Severe depression was more common among suicide attempters (30/44 cases). Conclusion. This study provides novel evidence that the association between inflammation and depressive symptom severity is present only in patients with a history of suicidal behavior. Elevated CRP may therefore represent a potential marker for identifying MDD patients at increased risk of suicide.