As recently as 2002, an international group of leading neuroscientists found it necessary to publish a statement arguing passionately that attention deficit hyperactivity disorder was a real condition, according to a story in the New York Times.
In the face of “overwhelming” scientific evidence, they complained, A.D.H.D. was regularly portrayed in the media as “myth, fraud or benign condition” — an artifact of too-strict teachers, perhaps, or too much television.
In recent years, it has been rarer to hear serious doubt that the disorder really exists, and the evidence explaining its neurocircuitry and genetics has become more convincing and more complex.
Even so, there have beenstories that use attention (or its lack) as a marker and a metaphor for something larger in society — for the multitasking, the electronic distractions, the sense that the nature of concentration may be changing, that people feel nibbled at, overscheduled, distracted, irritable.
But A.D.H.D. is not a metaphor, according to the story. It is not the restlessness and rambunctiousness that happen when grade-schoolers are deprived of recess, or the distraction of socially minded teenagers in the smartphone era.
“Attention is a really complex cognitive phenomenon that has a lot of pieces in it,” said Dr. David K. Urion of Harvard, who directs the learning disabilities and behavioral neurology program at Boston Children’s Hospital.
“What we’re specifically talking about in kids with attention deficit is a problem compared to age- and gender-based peers in selective attention — what do you glom onto and what do you ignore?”
Moreover, the disorder occurs along a broad spectrum, from mild to extreme. Boys are more likely to be hyperactive and impulsive, girls to be inattentive. One reason many girls don’t get an “official diagnosis” is that those with the inattentive form may be well-behaved in school, but still unable to focus.
“There’s a lot we still don’t know,” said Bruce F. Pennington, a professor of psychology at the University of Denver and an expert on the genetics and neuropsychology of attention disorders. “But we know enough to say it is a brain-based disorder, and we have some idea about which circuits are involved and which genes.”