Depression is considered as a factor causing significant disability, mortality and healthcare costs and The third leading cause of disability which affects about 840 million people around the world. There are some biological, psychological and environmental theories explaining the pathophysiology of depression, though the main reason is still unknown. Vitamin D as a unique neurosteroid hormone may have an important role in the improvement of depression. Although the relationship between vitamin D levels and depressive symptoms has been explored, the results are inconsistent. Evidences about the relationship between vitamin D deficiency and depression are in conflict. Many studies indicted that, taking vitamin D supplements can be considered as a useful interventions for depressed patients with vitamins deficiency. The current review study suggests that, higher vitamin D intake may be associated with a lower prevalence of depressive symptoms. Neurons and glia in many parts of the brain such as the cingulate cortex and hippocampus have vitamin D receptors. There are different brain process which vitamin D invovlved including; Neuroimmunomodulation, regulation of neurotrophic factors, neuroprotection, neuroplasticity and brain development are kinds of brain processes. This fact demonstrates that vitamin D might be associated with depression and its supplementation might play an significant role in depression and its treatment. Keywords: Vitamin D, Cholecalciferol, Depression, Treatment, Supplementation Citation: Zahedi M, Razavi A, Sajjadi M, Nasirzadeh A. The effect of vitamin D on depression in individuals. Int J Med Rev. 2019;6(3):77-80. doi:10.29252/ijmr-060302.