I agree with Polarbear. "Drifting off into a fog" can be due to a number of reasons, not necessarily ADHD.
Neurofeedback can give you a more definitive, objective answer as to whether ADHD is present or not based on actual brain wave activity. It's now being used to treat ADHD and other brain-based issues. My ds7 is 2e and has been in/out of neurofeedback for the past year.
I had no idea my ds was eg/pg until I placed him in a private gifted school after he shortly turned 5 and started to read/write more. Up until 5 and pre-k, he had been in special needs for pre-k. Bright, yes. But giftedness, we didn't have much evidence until he started to read/write more from vision therapy.
Ds, too, was diagnosed as having ADHD. I went to a 2e specialist last June and we talked about neurofeedback then based on comments on read on this forum. I have since learned that the ADHD diagnosis was a misdiagnosis. So I'm glad we didn't rush to medicate him or listen to what many people suggested we do.