Clinical depression is the kind of ailment that can sneak up on you, ruin your attitude, destroy motivation and lead to a multitude of other mental health issues. It can be managed if you're aware of it, but a lot of depression goes undiagnosed. It doesn't have to be that way--researchers think that smartphones could one day serve as an early-warning system by passively monitoring your behavior.

http://www.engadget.com/2015/07/15/r...se-depression/