world health day 2017, celebrated on 7 april, aims to mobilize action on depression. this condition affects people of all ages, from all walks of life, in all countries. it impacts on people’s ability to carry out everyday tasks, with consequences for families, friends, and even communities, workplaces, and health care systems. at worst, depression can lead to self-inflicted injury and suicide. a better understanding of depression – which can be prevented and treated – will help reduce the stigma associated with the illness, and lead to more people seeking help.