¹Wan Fang Hospital, Taipei Medical University, Department of Psychiatry, Taipei, Taiwan, ²School of Medicine, College of Medicine, Taipei Medical University, Department of Psychiatry, Taipei, Taiwan

Background: Depression significantly contributes to the global burden of morbidity, with associated cognitive and functional impairments, which are often linked to brain pathology in patients with major depressive disorder (MDD). Neuroimaging studies have revealed compromised neuroaxonal integrity in patients with MDD. Neurofilament light chain (NfL) may serve as a biomarker to reflect such integrity.

Aims & Objectives: Our study aims to compare plasma NfL levels between healthy controls and drug-free MDD patients and explore changes in NfL after antidepressant treatment in drug-free patients with MDD.

Method: We recruited 18-65 year-old drug-free patients with DSM-5 diagnosis of MDD and age-matched healthy controls, and used Montgomery-Asberg Depression Rating Scale (MADRS) to assess patient’s depression severity at baseline, week-4 and week-8 after antidepressant treatment. We compared NfL level between drug-free patients and healthy controls. We compared NfL level before and after 8 week of antidepressant treatment. Additionally, after 8 week of antidepressant treatment, we define patients with more than 50% improvement in MADRS as responders; those with less than 50% improvement in MADRS are non-responder. Finally, we compared NfL level between responders and non-responders.

Results: A total of 12 patients with MDD and 13 healthy controls were recruited. We did not find a significant difference in NfL level between patients with MDD and healthy controls (7.4 ± 6.3 pg/mL and 10.4 ± 7.8 pg/mL, respectively, p = 0.30). No significant plasma NfL level change before and after 8-week antidepressant treatment in patients with MDD (6.3 ± 1.8 pg/mL at baseline and 8.5 ± 2.5 pg/mL at week-8, p = 0.15). No difference in plasma NfL levels (at baseline, at week-8, and changes before and after 8-week treatment) between responders and non-responders.

Discussion & Conclusions: Although it is a study with small sample size and negative findings. Whether NfL changes after longer follow-up warrant to be studied.