Results obtained from these salivary biomarkers offer insight into individuals’ stress levels, anxiety or depression, primarily using salivary cortisol, immunoglobulin A (sIgA), salivary alpha-amylase, chromogranin A, lysozyme, melatonin, and fibroblast growth factor 2 (FGF-2). The gene discussed is FGF2; the disease is depressive disorder.