I think there is also a category of Disorganized attachment which is a combination of advoidant and anxious. The person approaches because they truly do want to attach to an another, but then the level of anxiety increases and fear of being overwhelmed or engulfed sets in and the person detaches and she moves away again. This cycle can be repeated over and over again, until the person is exhausted and just gives up or the person she is trying to relate to walks off in frustration. This is me. On one level, I want to attach and have intimacy, but the anxiety of having to be vulnerable, trust and give up my independence (fear of dependency) makes me push away and "go it alone."
But as Perna says, this was all learned through my early experiences in childhood and the world is not that way anymore because I am an adult. What worked when I was a child and helped me survive, is no longer a workable way of functioning and relating in the adult world. As I've started to recognize my pattern of relating, I get more skilled at circumventing my dysfunctional way of relating to others. It's not an easy process but it changing! Interesting thread.