#10 As a child, 22 record Olympic medal holder, Michael Phelps was diagnosed with ADHD or Attention Deficity hyperactivity disorder. Due to this disease, he finds it hard to focus on studies in class. He was just in 6th grade when this diagnosis came into picture. To get rid of the problem he started taking Ritalin. It helped him but it was shameful for him to go to the school nurse everyday during the lunchtime. Finally, when he was 12 years he stopped taking medicines and started swimming to get rid of his disease by physical training.