ADHD is a made up disease. Since if it wasn't, then all the "neurotypical" people would have monk level of equanimity and be able to start meditating for hours, reaching Samadhi on their first attempt. Yet they can't. Why? Because their mind is flooded with random thoughts, impressions and they can't just sit calmly. What makes them different from ADHD "sufferers" then? Lack of ADHD symptoms is almost synonymous with first stage of enlightenment.
ADHD is so common nowadays because people ignore their natural vocation and instead force themselves to pursue things they aren't really interested in because they think it gives them a status. You notice how ADHD is way more talked about among stemfags and not humanity fags? Because STEM attracts more people who lack interest in the subject.
Also having ADHD means struggling with your intellectual pursuits. But most people don't have any intellectual pursuits, hence they cannot notice their ADHD ,to be diagnosed implies you're at least trying something, but what you're trying you're not really interested in, you just didn't want to choose a more down-to-earth career path like most people do, but instead you prefer to be a pseud, which also explains that pic. Try doing routine boring labour like putting bricks or being a cashier and your ADHD disappears, of course you'd be bored, but you'd still do it, for some reason it only manifests when you have to use intellect, so all the "unable to focus" kind of thing is bogus.
Even if there are any brain differences, it doesn't mean it proves ADHD, those brain differences might instead indicate people prone to be pseuds.
By the way, this is also why meditation is a way out of ADHD. If you follow any Buddhist or Hindu meditation tradition, you would notice that half the advices sound like for people with ADHD, but they are just for all the ordinary people.
I say this as someone who thought he had ADHD and been using amph for a year in the past.