The World Health Organization has reported that four of the ten leading causes of disability in the US and other developed countries are mental disorders. By 2020,Major Depressive illness will be the leading cause of disability in the world for women and children. ▪The World Health Organization has reported that four of the ten leading causes of disability in the US and other developed countries are mental disorders. ▪By 2020, Major Depressive illness will be the leading cause of disability in the world for women and children