DS switches back and forth between his books and his computer games. He used to bring multiple books to school each day and read them there whenever the teachers would let him. He brings them in the car, even quick trips, to stores, to waiting rooms even if we're just going to have to wait 2 min. etc. I always saw it as a way to try to stimulate himself when he's bored. There are times when I would rather he do something else, for instance play with the other kids rather than reading a book at recess. I think he was doing that because he found the books more rewarding than whatever was going on with the kids. (usually they would be doing some sort of physical game that DS was just not interested in because he has motor issues). I am mildly worried about DS using it as an avoidance techinique but would worry more, however, if he was having meltdowns if he couldn't have books for a short period of time. That sounds more abnormal to me. People need to be able to cope in a world when they can't have whatever they want at all times, KWIM? I would definitely bring that up to the psych.
