I'm also diagnosed with this "made up mental illness", textbook ADD (not hyper) since elementary through my doctorate studies. At this point in my life, I see how the symptoms are so similar to hypothyroid (for me) and wonder how long I have been suffering a weak thyroid, Iodine deficiency.
I also take high doses (1-2g day), it suits me and my needs very well. Around the same time I started Iodine (last October), I started high quality oils (coconut, fermented cod liver oil, pastured raw butter), cut all vegetable oils, and adopted my own Weston A Price type of diet. I think that ALL has effected my ADD symptoms.