I have had them for 25 years since age 5, I am now 30 with 2 kids. So I would say outgrowing them is pretty rare. I was recently put on Lamictal and it does seem to work, however I have other issues that could counteract the medication. It is really just something he has to learn to live with and adjust to. Its not easy thats for sure, but with the right medical support and family support he will do just fine.
You didn't mention the age of your son or the dosage of Lamictal. Lamictal is a pretty good drug but without the other information, it is difficult to make any suggestions.