Biomarkers known to play a role in depression, such as BDNF, NGF, VEGF, IGF1, Ang, Nrg1, IL-6, and TNF-α, will be measured using advanced techniques like enzyme-linked immunosorbent assay (ELISA), Western blotting, and immunoprecipitation kits. This evidence concerns the gene BDNF and depressive symptom measurement.