I don't agree. I was clinically depressed in my early twenties. There is a temptation to reduce the world to simple bite sized physical causes. With something l

I don't agree. I was clinically depressed in my early twenties. There is a temptation to reduce the world to simple bite sized physical causes. With something like brain cancer this may be appropriate - but perhaps not, it may be that stress levels induced by a working environment may influence the chances of developing the disease. The point is there is a complex network of interactions which include emotional reactions to your environment, which can drive a person into a depressed state. It may be that for some proportion of those that suffer from depression that the cause is purely chemical imbalance driven by phenotypic makeup. But I suspect this is rare, we are a complex system of interacting components and these components include our own internal way of viewing the world. There is something tempting about reducing complex issues which have implications about the way we live our lives (like ADHD, Depression, etc) to simple physical reductionist causation. It is not a correct way of viewing the world and should be resisted.