Children with diagnoses such as ADHD, Anxiety, Dyslexia, Dysgraphia are all wired differently than someone with out it. Their neurological pathways literally function differently than those with out those conditions, similarly to children who have only one leg, and literally can't walk and function the same as children with two legs. It's the same thing. Just because you can't see a disability does not mean it is not there, and accommodations don't need to be made. What is also true of children with these diagnoses is they have AMAZING gifts!! Their brains have had to learn to make their own little accommodations which often times activates parts of their brain people with out those diagnoses may not use.
A term in recent years has been coined for these individuals, which is "twice exceptional" which is quite fitting. Historically, there has been a stigma around children with diagnoses such as this due to a complete lack of understanding. Personally, I see it as a gift. Here's a great video on being twice exceptional. Twice exceptional may bring unique challenges, but it can also bring amazing gifts too.