Comment by munk-a

I think this is a much better expression of your point as it makes clear that there is a correlation within a subset of people who have ADHD - rather than implying that all people with ADHD were exposed to trauma as children. Everything brain related is extremely complicated and there are quite a few comorbidities that have already been identified (the ASD-ADHD link for instance) and it's quite possible there is a link for some people between their developmental environment and neurological processing. That overlap isn't all-inclusive though - a fair number of people with ADHD grew up in wonderfully supportive environments.

Brain stuff - it just ain't simple.