"i&#039;m 16, and have been taking concerta for about a year now. it works well and really helps me focus, but i do have a lack of appetite and trouble sleeping. neither of those are really bad though. my 2 biggest complaints are first that i feel less creative while i&#039;m on it and second, when i don&#039;t take it now my concentration is horrible, and i get less done than before i started taking it."