Evidence showed that neuroaxonal damage was linked to a major depressive illness and that neurofilament light chain (NFL) is a biomarker of neuroaxonal injury. Furthermore, proinflammatory cytokines were found to be linked to serious depression as well as neuroaxonal damage. For the measurement of NFL and proinflammatory cytokines, as well as the evaluation of executive function, 40 patients with severe depression and 40 age- and sex-matched healthy controls were enlisted by the researchers for a study. The relationship between NFL levels, proinflammatory cytokine levels, as well as executive function was investigated using the general linear models. NFL levels in patients suffering from severe depressive disorder were substantially greater (P=.007) than in control subjects. The log-transformed levels of tumor necrosis factor-α (P=.004) were positively associated with NFL levels. Higher levels of NFL (P=.002) and tumor necrosis factor-α (P=.013) were linked to worse executive function impairments. NFL was discovered to be a new biomarker for serious depression and concomitant executive impairment through this study. More research was needed in order to determine the function of NFL in the pathophysiology of major depression and the cognitive impairment that it causes.