stealing food and lying. | ADHD Information

hello, i am hoping that someone may have some answers for me on a problem that i am having with my 13 year old son. he has been dignosed with adhd now for about 6 or 7 years. he has been stealing food ass well as lying, even sometimes when he doesn't need to. even though we take things and punish him he seems to go rite back to his old ways. he has a habit of hiding food behind the couch behind his bed or anywhere he can. my wife and i are so frustrated with the lying that we are in the progress of trying to find psychological help for him. it seems to be hard because we don't know what kind of person we should be talking to to get the best help. by the way, this is with him taking medication like aderall. what can we do when regular punishment and restriction seems to do nothing.