Were your diagnoses the result of a full assessment or an interview with a doctor or therapist?
It is expensive, but a good assessment is important.
As a professional, I am extremely unimpressed with the standard Vanderbilt or SNAP forms that most medical offices use. They only say “Yes, those symptoms exist” but they are not normed well (if at all), nor are they good for differential diagnosis.
I am partial to neuropsychologists, but the individual is more important than the letters after the name.
Also be aware that the longer someone goes without their ADHD well managed, you can develop secondary issues from the frustration.