Could depression be a form of 'sickness behaviour'? Barely a week goes by without a celebrity “opening up” about their “battle with depression”. This, apparently, is a brave thing to do because, despite all efforts to get rid of the stigma around depression, it is still seen as some kind of mental and emotional weakness. But what if was nothing of the sort? What if it was a physical illness that just happens to make people feel pretty lousy? Would that make it less of a big deal to admit to?