Geoff Watts meets researchers trying to find a new way to fight depression by studying those who never get it.
In the second of two programmes Geoff meets scientists at the University of Manchester, studying the brains of people who have undergone traumatic life events without becoming seriously depressed and comparing them to the brains of those people who do.
The hope is that new psychological therapies or even preventative medications might be developed to treat the one in five people who will at some point in their lives, become clinically depressed.
(Image: MRI scan of the head and brain. Credit: Corbis Royalty Free)