Vitamin D deficiency is evident in many parts of the world, even in the sunnier regions, for a variety of reasons. Recently, vitamin D has been reported in many scientific researchers as an important factor that may have significant health benefits in the prevention and the treatment of many chronic illnesses such as depression. According to the Global Burden of Disease Study, depression is one of the world's leading causes of disability and affects 350 million people in all communities across the world. Depressive disorders often start at an early age; they reduce people's functioning, and they are the leading cause of disability worldwide in terms of total years lost due to disability. The demand for curbing and preventing depression is on the rise globally. The present review will highlight the relation between vitamin D deficiency and the risk of depression among the different population. It will also discuss the epidemiology of vitamin D supplementation and depression from a variety of sources both suggesting and disproving their relation
