We tried stimulant medication to see if this was correct and also to aid his concentration at school in the hope of accelerating his learning.
We discovered that my sons ADHD in fact suppresses his ASD. While medicated he was so sensory adverse, so very anxious, all his senses were heightened. We tried for about 4 months trying different meds and doses. It didn't work. He couldn't function, his grades didn't improve- yes he could concentrate better but his dyslexia was his biggest barrier here.
Now he isn't medicated, his ADHD sometimes seems noticeable sometimes not. At the moment he is manic but happy. We will consider medication again in the future but for now he copes better when his ADHD distracts his ASD.