I had ADHD was I was younger, I’ve been issued a Class 2 JAR licence, and I’ve been told a Class 1 won’t be affected. However, I was on Ritalin when I was younger and I would have been refused a medical if I was still on that now. I’ve not heard of Dex before or know any of the side effects etc. Best thing to do is speak to them with the letters from your physiatrist next time. Good luck