Thank you for your last postings and your email, especially your comment about evolution as "a satisfying conceptual organizer to psychology's many findings and mini-theories." The ethologists would probably describe all of our theories as plumage elaborated by diversity that was pushed by competition. (The Darwinian truth of "publish or perish"?!)
Hyperfocus ... Sure people can do it; Kathy Nadeau and Ned Hallowell certainly are among them. And both of these speakers describe themselves in ways strongly suggestive of ADD (with or without the H). However, "hyperfocus" in itself seems to be a talent that is inconsistent with ADHD, either by DSM 4 terms or by Barkley's Executive Function Model. If we look upon our minds as a network of Adapted Systems, then some of the adaptations may have impulse problems and impaired Executive Functions; others, especially the older ones, may not. (1) For example, I know a bright lady who loses car keys and hates her managerial paperwork; she also will get into extended power fights (mania?) and is absolutely non-ADHD in such wars, although still impulsive.
ADHD & ADD Gossip ... There's speculation from Barkley and others about ADHD becoming a "Behavior Inhibition Disorder" with DSM 5. It would have a BID acronym? Is that a pun with stimulant dosage schedules? It could be TID (Triune Impulse Disorder!) if we stick with the trinity of impulsiveness, poor sustained attention, and hyperactivity!
There is responsible speculation (at the November '96 ChADD conference) that ADD may be a parietal issue whereas we H types have a frontal deficit. It makes sense for the distractible, preoccupied individuals to have difficulty with sensory input, perhaps involving more newly evolved mechanisms for lateral inhibition between cortical sensory mechanisms. There's also some feelings (Tom Brown, PhD, Yale Univ) that methylphenidate has a greater benefit for ADHD whereas Dexedrine may do ADD more good. If there is a differential pattern of dopamine activity in frontal areas and noradrenergic in the parietal sections, then all the rumors hang well together.
NOTE:
(1) Pennington B. (1991) Diagnosing Learning Disorders: A Neuropsychological Framework. New York: Guilford. Suggests the newly evolved learning abilities are the most sensitive to disruption. Thus, executive functions and social skills may be less than complete while olders systems remain intact.