"i have been taking this for 10 years (started at 18 mg, went up to 36 mg). recently (several months ago), i developed several horrible side-effects. for example: it made me feel nervous. i could not keep still. it also made me extra irritable (to the point i was yelling at my friends for the littlest things). i also felt depressed (to the point i did not want to get out of bed at all) and could not sleep. the doctor brought me down to 18 mg, symptoms did not improve. i immediately stopped taking this and felt 100% better the next day. the doctor put me on adderall xr which works a lot better with very little side-effects. please avoid concerta if possible."