First, no significant difference was found on NfL CSF levels between patients diagnosed with a psychiatric disorder and controls, whereas both were found significantly lower in contrast to neurodegenerative or neurological disorders, Moreover, NfL CSF levels have shown the best AUC (0.94, 95% IC 0.89-0.98) among other biomarkers such as Aβ1-42 or P-tau, selecting an optimal cut-off value of 1332 pg/ml with a sensitivity of 87% and a specificity of 90% to distinguish between neurodegenerative and psychiatric disorders (4). This evidence concerns the gene NEFL and nervous system disorder.