I think you are right to get him checked out it does sound as if there is something going on, your Doctor will hav other ideas how you proceed Good Luck
He has been in counsling for 5 years. We started counsling with him a long time ago because we felt it was hard on him when we got custody and he was taken away from his mom. The cousler told me that since he is back by his mom he is reverting back to being a baby to try and gain her love. For 5 years she would pay no mind to him and when we move close to her it is more convient for her to be a mother. She has no excuse now for not seeing or calling him. About 3 years ago he molested my two younger daughters and social services told us that about a report they got from a parent of a kid he was bragging to about it. My hudband and i think that while he was at his mom house one summer it happen to him. Her new husband is not stable and his family is kind of diffrent and he had younger teenage brothers. When my son visited there that is where they all lived. He would act very diffrent ever summer he came home from her house. My husband and I are so cautious about who our children are around. We would have never guessed that our son would be someone we had to look out for, not to hurt the other children. After reading some things on this website. I think I know what he might have Endocaprises ( spelled something like that) I actually set up a doctors appointment. Hopefully this will be the answer to a long long battle.
Perhaps he is upset about something in his life and this is his way of expressing it, sounds like a cry for help, maybe get some counseling as I think there is more going on ,perhaps a school counselor, how does the teacher and school handle this if he does this at school,other than calling you. I doubt if punishments like hitting him or taking his things away will do any good, ,get some help to find out Why he is doing it.