Just thought I'd mention this. It's called Bye Bye Happiness and looks at 4 people and their different experiences of depression - ranging from manic to post-natal. Radio Times says..
"...uses re-enacted scenes to re-create the quartet's reactions to discovering they had depression, expores their black, even suicidal moods, and touches on their unwillingness to discuss it because of the stigma attached and their ways of coping."
One off documentary.