A.L.
I saw a really scary show on A&E (I think). The show was called Intervention. Apparently a girl started not swallowing food at a very young age. Doctors couldn't figure out what was wrong and the girl lost so much weight she had to be fed intravenously. Found out through counseling that a very good friend of the family was molesting her and making her swallow. It really messed this kid (now a grown woman) up. I'm sure this is a VERY extreme scenerio but I wanted to give you the info.
I have a 7 year old too who is very smart and I know that if this was happening at our house I would have to be careful about giving it too much attention. I think my son would really thrive on the extra attention that this brought to him and would try to use it to his advantage.
Good luck to you.