At a glance

More than 350 million people of all ages suffer from depression worldwide, according to the World Health Organization.

WHO lists depression as the leading cause of disability and a major contributor to the global burden of diseases. The causes of depression are still unknown, but it is believed that genetics, illnesses including brain trauma, medications and life events can all contribute to the illness.

Studies suggest women are twice as likely to get depression, and that people in rich countries have a slightly higher risk of depression than those from low-to-mid-income countries.