News.com has an interview with Dr. Edward Hallowell, a psychiatrist who’s studied attention deficit disorder for more than a decade:
[ADT is] sort of like the normal version of attention deficit disorder. But it’s a condition induced by modern life, in which you’ve become so busy attending to so many inputs and outputs that you become increasingly distracted, irritable, impulsive, restless and, over the long term, underachieving. In other words, it costs you efficiency because you’re doing so much or trying to do so much, it’s as if you’re juggling one more ball than you possibly can.
Symptoms: When people find that they’re not working to their full potential; when they know that they could be producing more but in fact they’re producing less; when they know they’re smarter than their output shows; when they start answering questions in ways that are more superficial, more hurried than they usually would; when their reservoir of new ideas starts to run dry; when they find themselves working ever-longer hours and sleeping less, exercising less, spending free time with friends less and in general putting in more hours but getting less production overall.