"i&#039;m 17 and have been taking this for about a month now for adhd. i started at small doses of ritalin (10 mg) and then moved to 20 mg. my doctor thought it would be easier to just put me on concerta since it&#039;s 18 mg a pill. i then took 36 mg of concerta which didn&#039;t work out. i got major irritability and started feeling depressed. even my focus was off. i went back down to 18 mg and it&#039;s working much better. no irritability, depression feeling. make sure you&#039;re on the right dose for your body, too much can do more harm and too little may not do any thing."