Well, I have Attention Deficit Disorder, Generalized Anxiety Disorder, and Dyscalculia.
Attention Deficit Disorder, or ADD for short, is perhaps one of the most well known and widely diagnosed developmental disorders across the United States and is largely a copout used to net schools money and for parents to have an excuse for why their child won't pay any goddamn attention. That said, I actually have a true case of it. I'll be in the middle of doing something, likely quite important, and then I'll notice something completely insignificant... say like a fly buzzing by, or a dirt stain on the counter. My attention will completely focus on that thing for a moment, and I'll completely forget what I was originally doing. This has had a very nasty impact on my studying habits, though I've learned how to reel myself in quite a bit. Martial Arts helps, meditation can help focus. Also, avoiding Wikipedia...
Generalized Anxiety Disorder is not a developmental disorder, as Dyscalculia and ADD are. Instead, due to some unknown trigger, my body will immediately go into a "Fight or Flight" response to stimuli I'm not even aware of. The adrenal glands began pumping adrenaline into my bloodstream. I become panicked for no good reason. My heart begins to race. I overract to everything. If it happens at work, I need to leave for the day.
Lastly, the little known Dyscalculia. Otherwise known as Dislexia for numbers. Now, I'm not nearly as bad as some of the sufferers of this disorder. However, that said, while I'm trying to do math quickly, I end up reversing numbers. Say I have to figure out 76.53 multiplied by 29.38 for some reason. Well, I'll end up multiplying 67.35 by 92.83, and never realize my mistake. I also have a hard time doing math quickly for whatever reason. The numbers just don't leap into my head like they do with other people. I actually have to count out 7 x 8.