Application of Near-Infrared Spectroscopy in Early Detection of Antidepressant Treatment Efficacy in Major Depressive Disorder: A Longitudinal Study.

Background: Major depressive disorder (MDD) is a prevalent and debilitating mental health condition, necessitating early detection and effective treatment strategies. Near-infrared spectroscopy (NIRS) is a promising neuroimaging technique for monitoring cerebral hemodynamics and may serve as an objective biomarker for MDD diagnosis and treatment efficacy. This study aimed to investigate the utility of NIRS in the early detection and longitudinal monitoring of antidepressant treatment efficacy in MDD patients.

Methods: This longitudinal study, conducted from May 2022 to May 2024, included 138 participants. After propensity score matching analyses, 80 were included, including 40 MDD patients and 40 healthy controls matched for age, gender, race, education, height, weight, and body mass index (BMI). Participants underwent NIRS measurements during cognitive tasks, including verbal fluency, sustained attention (e-primer), and one-back memory tests. Clinical assessments were conducted using the Hamilton Depression Scale (HAMD), Hamilton Anxiety Scale (HAMA), Clinical Global Impression (CGI), Continuous Performance Test (CPT), and one-back tests at baseline and after treatment at 4 weeks and 24 weeks. Statistical analyses were performed to evaluate changes in oxygenated hemoglobin (HbO) and deoxygenated hemoglobin (HbR) levels and their correlation with clinical outcomes.

Results: At baseline, MDD patients had significantly lower HbO and higher HbR levels compared to controls (p < 0.01). After treatment, HbO increased (4.77 ± 1.23 to 5.37 ± 1.21 µmol/L, p < 0.05) while HbR decreased (3.46 ± 0.98 to 2.91 ± 0.96 µmol/L, p < 0.05) in the MDD group. However, these levels differed significantly from controls at 4 weeks (p < 0.01). By 24 weeks, HbO further increased (6.01 ± 1.08 µmol/L, p < 0.05), and HbR further decreased (2.19 ± 0.71 µmol/L, p < 0.05), with no significant differences from controls (p > 0.05). Clinically, MDD patients showed significant improvements in HAMD, HAMA, CGI, CPT, and one-back scores over 24 weeks (all p < 0.05). At 4 weeks, HAMD, HAMA, and CGI scores were higher, and CPT and one-back responses were lower than controls (p < 0.01). By 24 weeks, HAMD, HAMA, and CGI scores remained higher (p < 0.01), and CPT and one-back responses were lower than controls (p < 0.01).

Conclusion: This study underscores the potential of NIRS as a non-invasive, objective tool for early detection and monitoring of treatment efficacy in MDD. The significant correlations between NIRS findings and clinical improvements highlight its utility in personalized treatment strategies, paving the way for more effective management of MDD.