I'm asking cuz my son has been on Concerta for 5 mos and it seems like it's not working as well anymore. I NEVER thought it worked at home, but school was saying he was much calmer and could focus (I don't see that at home at all). Now one of his teachers is saying he's getting less and less focused again, although other teachers are saying he's still focused. So do their bodies get used to a certain dose after months or a year and it needs to be adjusted upwards? He has not grown appreciably in height or weight in 5 mos so it's not that he's bigger and the dose would need to go up, too. Just seems to be wearing off? Body getting used to it? Is that possible?