I see my characters in exactly the same way. I just have so many stories for them that I think about a lot, but barely ever write down or draw out because I just can't find the words, or there's too much to illustrate... They're like people in their own worlds, sort of. & I've never been formally diagnosed because I get too nervous at the doctors to properly talk about anything but I'm about 90% sure I have Aspergers. I don't really know, but I fulfill the DSM IVTR requirements for a diagnosis, anyway.
I don't have aspergers but I am "intellectually gifted", this for me brought more problems than advantages, I have been bullied and because of that I changed schools constantly causing me to not have any friends.. I think drawing in class might've been a way of avoiding communicating with other students, since I always had my schoolwork and tests finished first in class I needed something else to spend my time and that was drawing.
Now I am so glad that I don't have to attend school any more and since a few years I have become a bit more serious about making art..