Considering the fact that I read about 3-4 novels a week, I would say that for me it's more of an escape from "reality". I can delve into another world and lose myself in the characters and the world that the writer creates. Sometimes having something to "escape" into can save one from stress and I like to think that by using reading as my outlet, most of the time I'm pretty calm.
I don't think I would consider reading an addiction. I feel as though it's just an extension of my mind that I choose to read many books. I learn so much about writing and ways to hold a reader's attention, so it helps whenever I'm writing as well. I suppose that everyone needs to find something to do that keeps them sane, and for me that's reading books and learning from the authors and characters in the story.