ADHD doesn't display symptoms in adulthood because it's not real. It's a made up diagnosis for doctors and teachers that don't know what else to do or that do not want to be inconvenienced with a child that has an overactive personality. Doctors are all too quick to diagnose ADHD to a desperate parent that really wants to help their child. Suddenly it disappears in adulthood? No other illness does that so why ADHD? I don't believe it exists. I believe some children have difficulties and that they may need specialized care, but I don't believe that the majority of children on ADHD meds need anything other than patience and understanding.