Go to Zorgkaart Nederland (Dutch care map) of the Patiëntenfederatie Nederland (Netherlands Patients Federation) and leave a rating (anonymously).
You have to fill in a declaration of health when you apply for a driver's license at the CBR. One of the question is whether or not you have ADHD. What applies to your case specifically and what you need to do is described on the CBR's site.
If you use ADHD medication, you have to bring a doctor's letter when you travel. The Opium Law covers ADHD medication.
On the CAK's website, you can read about which letter you need for which countries. Usually it is sufficient to have a letter written by your GP or pharmacy.