5-hydroxyindole acetic acid level in cerebrospinal fluid as a potential biological marker for suicide

Objectives: This study aimed to investigate the potential use of cerebrospinal fluid (CSF) 5-hydroxyindole acetic acid (5-HIAA) as a biomarker for suicidal behavior. Materials and Methods: Seventy-one autopsy cases were included in the study, of which 35 were classified as suicidal cases and 36 as non-suicidal cases. The median 5-HIAA level in the CSF was measured and compared between the two groups. Receiver operating characteristic (ROC) curve analysis was used to establish the diagnostic accuracy and optimal CSF 5-HIAA cutoff levels for discriminating suicide from non-suicide. Statistical analysis: The statistical analyses involved t-tests, Mann-Whitney, chi-square, and Fisher exact tests as appropriate. ROC curves assessed the diagnostic value of CSF-5-HIAA, and the p-values less than 0.05 were considered statistically significant. Results: The ROC analysis revealed a threshold value of 87.64 nMol/L for 5-HIAA, with a sensitivity of 54% and specificity of 86%. The median CSF 5-HIAA level was significantly lower in suicidal cases compared to non-suicidal cases (86.27 nMol/L vs. 107.06 nMol/L, P = 0.001). Conclusions: The study suggests that CSF 5-HIAA may be a potential biomarker for identifying suicidal behavior. This finding could contribute to developing more effective prevention and treatment strategies for suicide and suicidal behavior.