Yes, of course our life experiences and learning affect the development of personality and mental traits. And I guess that in most of the cases disorders like depression are triggered by life experiences. But there also seems to be a inherited factory, which in some cases is the main reason of depression. In a classical view genes were seen as unaltered by life experiences. But recent studies of epigenetic coding are indeed showing ways in which traces of life experiences are stored on top of DNA. So, my point is all about stepping over the dualism. Even our genetic inheritance is not "purely biological", it is affected by the emotions, thoughts, memories and unresolved traumas of our ancestors. (No, I'm not to say that genes would determine all of our psychological build - they just contribute towards certain traits, and the rest is learnt. So it is always interaction of all the different layers of existence)

But, yeah, at least in western culture we have a long tradition of body / mind and matter / soul -dualism, so it isn't always easy to understand how these layers are interconnected. Maybe I'll post more about that later on =)