The function of klotho is complex and multifaceted, with known roles in regulating insulin,4 Wnt,13 fibroblast growth factor,14 nuclear factor kappa B,22, 51 tumor necrosis factor-α22, 52 and N-methyl-D-aspartate receptor signaling.12 Importantly, each one of these pathways, which may be dependent or independent of the aging process, can be linked directly or indirectly to stress or depression. This evidence concerns the gene KL and depressive disorder.