Abstract
BACKGROUND: Suicide is among the severe outcomes of mental illness and has been reported to be associated with neurodegeneration and cognitive impairment. The blood neurofilament light chain (NfL) level is a biomarker of neuronal damage in neuropsychiatric disorders. This study investigated whether the NfL levels are associated with lifetime suicidal behaviors and whether this level is higher in patients with major depressive disorder (MDD) compared with healthy controls. METHODS: In this cross-sectional study, we included 73 patients with MDD and 40 age- and sex-matched controls. The blood NfL levels were measured using an enzyme-linked immunosorbent assay. We compared the NfL levels between patients with MDD and controls and performed regression analysis to evaluate the association between the NfL levels and suicidal behaviors. RESULTS: Nearly half of the patients with MDD (43.80%) reported lifetime suicide attempts. Those with MDD had higher blood NfL levels, but their levels did not significantly differ from those of the healthy controls. Logistic regression results revealed higher risks of lifetime suicide planning (Odds ratio [OR] = 1.64) and suicide attempts (OR = 1.94) with every 10 pg/mL increase in the NfL levels. CONCLUSIONS: Our results demonstrate that higher serum NfL levels were associated with lifetime suicidal behavior.