"i have been using concerta for 15 days now. i started out with 18mg for a week and the second week 36mg. i haven&#039;t seen any difference by now, which is very dissappointing for me. in fact i feel slighly extra depressed than i already am, but no big difference. starting tommorow my doctor told me to take 54mg per day. any suggestions? is it too soon to see any difference?"