Depression is the second biggest cause of disability in the world, a review of research has concluded.
Experts writing in journal PLOS Medicine said the disease must be treated as a global public health priority.
Clinical depression was compared with more than 200 other diseases and injuries as a cause of disability.
Depression was ranked at number two globally, but affected different countries and regions in a range of ways. Rates of major depression are highest in Afghanistan and lowest in Japan.
In the UK depression was ranked at number three in terms of years lived with a disability.
Dr Alize Ferrari from the University of Queensland’s School of Population Health led the study.
She told the BBC: “What one person recognises as disabling might be different to another person and might be different across countries as well, there are lots of cultural implications and interpretations that come in place, which makes it all the more important to raise awareness if the size of the problem and also signs and how to detect it.”