Out of my four boy's, I have one son with ADHD and one with ADD. It is a big difference with the 2, my son with ADHD has the combined type and is more hard to get focused , he is also on a higher dosage of medication then the one that is ADD. They were diagnosed by a DOCTOR, on my asking if it might be possible that they had a problem.They had them seen by a team at the Cleveland Clinic and they were very thoro with the testings . School can not diagnose, just suggest that their might be a problen. Though my sister said that while going to school to be a teacher she spent time on ADD/ADHD and the signs that one has a problem and way's to suggest it to a parent. Also Rittalin is not a cure all for children! Their are other medications out their. My one son was started off on Rittalin and it turned him into the Zombie, after a month trial we had him off of it and put onto a different medication that was timed released., He is still active and all that but we can get him focused on tasks at hand.
www.cdc.gov/ncbddd/adhd/symptom.htm and
www.webmd.com/add-adhd/default.htm have information that might be helpful. Also Chadd.org is great for add/adhd information.