Association of Neurofilament Light Chain With the Antidepressant Effects of Low-Dose Ketamine Infusion Among Patients With Treatment-Resistant Depression

Abstract

Background The role of neurofilament light chain (NFL) in treatment-resistant depression (TRD) is unclear. Whether baseline NFL concentrations are associated with the antidepressant effects of low-dose ketamine infusion has not been determined. Methods The NFL concentrations of 71 patients with TRD and 17 healthy controls were assessed. Patients with TRD were randomly administered a single infusion of 0.5 mg/kg ketamine, 0.2 mg/kg ketamine, or normal saline. Depressive symptoms were assessed prior to infusion and sequentially at postinfusion timepoints (after 240 min and 2–7 and 14 days after infusion) using the Hamilton Depression Rating Scale (HDRS). Results After adjustment for age, sex, and body mass index, patients with TRD were more likely to have higher concentrations of NFL than healthy controls (p < 0.001). A generalized estimating equation model with adjustments for infusion group, age, sex, body mass index, and baseline HDRS scores showed that baseline NFL concentrations were positively associated with subsequent HDRS scores following low-dose ketamine infusion (p = 0.038). Discussion Higher concentrations of NFL were observed among patients with TRD compared with healthy controls. Baseline NFL concentrations may predict the antidepressant effects of low-dose ketamine infusion.