From Peter Gray's 'Freedom To Learn' blog

ADHD diagnoses derive from schools' intolerance of normal human Diversity.

According to the most authoritative recent data, approximately 8% of children in the United States, aged 4 to 17, have been diagnosed as having ADHD (Attention Deficit Hyperactivity Disorder).[1] The same reports note that the disorder is about three times as frequent in boys as it is in girls, so this means that roughly 12% of boys and 4% of girls have received the diagnosis. Think of it. Twelve percent of boys–that's approximately one boy out of every eight–has been determined by some clinical authority, using official diagnostic criteria set out by the American Psychiatric Association, to have this particular mental disorder!

If only teachers' ratings  were used, the numbers would be even greater. In one study involving 16 different schools and more than three thousand children, teachers filled out the standard ADHD diagnostic checklist of behaviors for the students in their classrooms.[2] In that study, where teachers' ratings were not averaged in with the ratings made by parents, 23% of elementary school boys and 20% of secondary school boys were diagnosed as having ADHD. What an amazing finding. By teachers' ratings, nearly one fourth of all elementary school boys and one fifth of all secondary school boys has the mental disorder, ADHD!

ADHD is Fundamentally a School Adjustment Problem

What does it mean to have ADHD? Basically, it means failure to adapt to the conditions of standard schooling. Most diagnoses of ADHD originate with teachers' observations.[3] In the typical case, a child has been a persistent pain in the neck in school–not paying attention, not completing assignments, disrupting class with excessive movements and verbal outbursts–and the teacher, consequently, urges the parents to consult with a clinician about the possibility that the child has ADHD. Using the standard diagnostic checklists, the clinician then takes into account the ratings of teachers and of parents concerning the child's behavior. If the ratings meet the criterion level, then a diagnosis of ADHD is made. The child may then be put on a drug such as Adderall or Concerta, with the result, usually, that the child's behavior in school improves. The student begins to do what the teacher asks him to do; the classroom is less disrupted; and the parents are relieved. The drug works.

The diagnostic criteria for ADHD, as outlined by DSM-IV (the official diagnostic manual of the American Psychiatric Association), clearly pertain primarily to school behavior. The manual lists nine criteria having to do with inattention and another nine having to do with hyperactivity and impulsivity. If a child manifests at least six of either set of nine, to a sufficient degree and over a long enough period of time, then the child is identified as having one or another version of ADHD. Depending on which set of criteria are manifested, the child is given a diagnosis of ADHD Predominantly Inattentive Type; ADHD Predominantly Hyperactive-Impulsive Type; or ADHD Combined Type.

Here, for you to peruse, are the complete lists of criteria, quoted directly from DSM-IV:

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