"People who think ADD means having a short attention span misunderstand what ADD is," says Kathleen Nadeau, Ph.D., a psychologist in Silver Spring, Maryland, and the author of ADD-Friendly Ways to Organize Your Life. "A better way to look at it is that people with ADD have a disregulated attention system."

scatteredminds.com

"The hallmark of ADD is an automatic, unwilled "tuning out," a frustrating non-presence of mind. People suddenly find that they have heard nothing of what they have been listening to, saw nothing of what they were looking at, remember nothing of what they were trying to concentrate on. One misses information and directions, misplaces things, and struggles to stay abreast of conversations. Tuning out creates practical hardships, and it also interferes with one’s enjoyment of life... ...This absence of mind is one cause of the distractibility and short attention spans which bedevil the adult or child with ADD, except around activities of high interest and motivation. There is an almost active not noticing, as if a person purposefully went out of his way to be oblivious of what is around him... ...The distractibility fosters chaos. You decide to clean your room which, typically, looks like a tornado has just passed through. You pick a book off the floor and move to replace it on the shelf. As you do so, you notice that two volumes of poetry by William Carlos Williams are not stacked side by side. Forgetting the debris on the floor, you lift one of the volumes to place it beside its sibling. Turning a page, you begin to read a poem. The poem has a classical reference in it, which prompts you to consult your guide to Greek mythology; now you are lost because one reference leads to another. An hour later, your interest in classical mythology exhausted for the moment, you return to your intended task. You are hunting for the missing half of a pair of socks which has gone on furlough, perhaps permanently, when another item of clothing on the floor reminds you that you have laundry to wash before the evening. As you head downstairs, laundry hamper in arm, the telephone rings. Your plan to create order in your room is now doomed... ...The distractibility in ADD is not consistent. Many parents and teachers are misled: to some activities a child may be able devote, if anything, a compulsive, hyperconcentrated attention. But hyperfocusing which exludes awareness of one’s environment is also poor attention regulation. Too, often hyperfocusing involves what may be described as passive attention, as in watching television or playing video games. Passive attention permits the mind to cruise on automatic without requiring the brain to expend effortful energy. Active attention, in which the mind is fully engaged and the brain has to perform work, is mustered only in special circumstances of high motivation. Active attention is a capacity the ADD brain lacks whenever organized work must to be done, or when attention needs to be directed towards something of low interest... ...A facility for focusing when one is interested in something does not rule out ADD, but to be able to focus the person with ADD needs a much higher level of motivation than do other people. Ignorance of this fact has led many doctors to miss the diagnosis. "Indeed, the characteristic of our patient," wrote a psychiatrist of a college lecturer I had diagnosed with attention deficit disorder but whose GP wanted a second opinion, "is that he is able to focus his attention on something that he is really interested in, which for patients afflicted with ADD is very difficult." That is not what is very difficult. What can be immobilizingly difficult is to arouse the brain’s motivational apparatus in the absence of personal interest. ADD is situational: in the same individual its expression may vary greatly from one circumstance to another. There are certain classes, for example, in which the ADD child may perform remarkably well, while in others she is scattered, unproductive, and perhaps disruptive. Teachers may conclude that the child is wilfully deciding when, or when not, to buckle down and work diligently. Many children with ADD are subjected to overt disapproval and public shaming in the classroom for behaviours they do not consciously choose. These children are not purposively inattentive or disobedient. There are emotional and neurophysiological forces at play that do the actual deciding for them... ...In a minority of cases, especially in girls, hyperactivity may be absent altogether. They may go through school inattentive and absent minded but, as they cause no trouble, they are "passed through" from grade to grade... ...Frequent and frustrating memory lapses punctuate every day in the life of the person with ADD... The moods of the ADD child are as capricious as the weather patterns El Nino has loosed upon the world. Happy smiles are transformed into frowns of displeasure or grimaces of despair in a matter of moments...The emotional states of adults with attention deficit disorder are also up and down without apparent rhyme or reason. Good days and bad days follow each other according to some mysterious calendar written who knows where and by whom."