I agree with Onward2wards. I think there's a difference. How one person responds to a life event is totally different from someone else, and in some people's cases situational depression can trigger a susceptibility to depression that turns it into something more clinical. I also think that depression can be your body's way of telling you that something in your life needs to change -- so it's a medical response to a particular situation. Depression as an illness is tricky because it either becomes wrapped up in our lives, or we become wrapped up in it. It can then get to the point that we can't extricate ourselves from our depression without changing our situation, but we can't change our situation without getting help for the depression. Eventually it becomes hard to tell where the situation starts and the clinical ends.