Neutrophil-to-lymphocyte ratio and C-reactive protein in persons with suicide attempts and psychiatric disorders: A cross-sectional comparative pilot study in Bangladesh

Background: Blood biomarkers showed some associations with mental health conditions . However, they remain inconclusive in predicting psychiatric disorders and suicide attempts. Identification of peripheral blood biomarkers for suicide prediction could enable early preventive measures as they are cheap and easy to measure. Objectives: We aim to compare blood biomarkers between people who have attempted suicide and who have psychiatric disorders. Methods: Data was collected for this cross-sectional study between July 2021 and November 2023 from 55 hospitalised patients categorised into two groups – suicide attempt (n=29) and psychiatric disorder (n=26). We measured the complete blood count and C-reactive protein (CRP).All statistical analyses were performed using the Statistical Package for the Social Sciences (SPSS) version 25 and were tested using a two-sided test, and a p-value of <0.05 was considered statistically significant. Results: The mean age of the participants was 26.1 (±10.0) years which was significantly lower for people with suicide attempts than for those with psychiatric disorders. The mean CRP level (p=0.011), total leukocyte count (p=0.024), neutrophil (p=0.002), and neutrophil-to-lymphocyte ratio (NLR, p=0.002) were significantly higher among people with suicide attempts, whereas the lymphocyte (p=0.002) and monocyte (0.029) were significantly higher among psychiatric patients. Conclusion: The findings showed NLR and CRP were more prominent blood biomarkers in suicide attempts than in psychiatric patients. However, due to the small sample size, caution is required when generalising the study results.