there is a word for that
'co-morbid' i think
its when you just happen to have two conditions at the same time
There is a very old episode of Dr House I saw years ago where he explains how weglaatbaar small the chance is to suffer from two things coincidentally

My training as someone who has worked with autie kids tells me that you are probably wrong. If an autistic kids presents with ADD symptoms, it is probably just symptoms of his autism and having ADD in addition is unlikely.
Well this is what I was taught.

Several things come to mind that would support your theory. but im tired now bye