My son has had his IQ tested every year (ages 3,4,5,6), it has always been 65. He was diagnosed with severe ADHD and we started him on medication. He has now been on the medication for a year and his IQ was retested (now 7 years old) and his IQ is now 100. I've always known he wasn't dumb, so I'm thrilled to see such a score, but is this normal for a young child to have such a large increase in their IQ score after starting ADHD medication?