Anxiety can cause many symptoms similar to ADHD, but ADHD is a totally different disorder. It's a neurodevelopmental disorder that begins in childhood/you're born with it. For some people, it continues into adulthood.

If you are really anxious, your heart rate will elevate making you feel restless, and he fight or flight responses prepares you to focus on the big picture rather than meddle in tiny details. I could see how anxiety causes similar symptoms and might be confused with a dual diagnosis of ADHD and GAD. That said, you'll have to talk to your PDOC. The ADHD testing is so darn expensive, but if your pdoc truly feels you may have ADHD, then he'll probably want you to have it done.