Russel Barkley is a pioneer in the field of ADHD research. I have heard of such a claim, but not from Russel Barkley. Could you provide a link of Russel Barkley making the claim please?
It's somewhere in this talk (broken down as a playlist). It's been a while since I've watched it but I do recall him saying that they can see physically differences in the brain of adhd folks
Seeing physical differences in brain volume, connectivity or activity between groups of many adhd folks and non-adhd folks is one thing and that can be done. However, performing a clinical diagnosis of adhd in an individual, solely based on a brain scan, is a completely different thing.
