My Brother is considered to have severe ADHD, but he scores well in Block Intelligence, which is considered to be pure intelligence, and not a by product such as working memory, which a lot of ADHD children may lack, and yet his overall IQ is somewhat low. ADHD may limit children in certain areas such as previously said working memory or logic, but it can help in certain areas such as abstract thinking, and perceptional thoughts. I most likely don't have ADHD of any form, but I do have about an IQ of 130, but remember, IQ is not an accurate way to measure TRUE intelligence.
To Doctor Mage, cracking your knuckles is actually good once in a while, because it stimulates your tendons there, preventing future sprains and increasing the flexibility there. However, doing it too much may cause sprains and other pains in your fingers, so only do it once in a while.
Also Sandvich, I'm sure you would LOVE to switch lives with me, with my ADHD pyromaniac brother, and my 2 annoying immature little sisters.