The National Institute of Mental Health (NIMH, as in “The Rats of NIMH” if you’ve read the book and/or seen the movie) has a very thorough PDF document about ADHD. You can download it (49 pages) or you can view it on the site. http://www.nimh.nih.gov/health/publications/adhd/complete-publication.shtml
NIMH info on ADHD
About the Author: Stephanie Sarkis
Dr. Stephanie Sarkis is a National Certified Counselor (NCC), Licensed Mental Health Counselor (LMHC), and AMHCA Diplomate and Clinical Specialist in Child and Adolescent Counseling based in Tampa Bay, Florida, where she specializes in the treatment of ADD/ADHD. Dr. Sarkis conducts evaluations, testing, diagnosis, and counseling services. She also is a public speaker, consultant, coach, and is a facilitator in collaborative law.