This is what I've said for many years. That the two had to be related because I've noticed the pattern in many families that I know who have more than one child with a mix of autism and ADHD. My husband's family being one of many families that I know that have this mix. I mentioned this a few years ago as a comment on an article regarding autism and I was yelled at from a someone about it saying that I was wrong and the two were totally unrelated. I'm definitely not an expert, but this is just what I've suspected just because of the visible evidence.