No, it is doubtful that being on Marihuana and Concerta will destroy your brain or something. I've heard of people using ADD meds recreationally and then smoking weed (LIke Cannada) and they're fine. Of course, if you trust your family doctor, you could ask him in confidence if that's okay. I trust my doctor a whole lot, and I would have no problem asking him something like that. It all depends on you.