Rollmops I entirely disagree with your perspective there. ADHD is nothing to do with being 'lively, boisterous or defiant'. There are three subsets of AD(H)D, and the diagnostic process is not easy. It is not an easy label to attach to any child. They have to display at least 6 of the symptoms in 2 different settings for at least 6 months:
What are the symptoms of ADHD?
Attention difficulties
A child must have exhibited at least six of the following symptoms for at least six months to an extent that is unusual for their age and level of intelligence.
* Fails to pay close attention to detail or makes careless errors during work or play.
* Fails to finish tasks or sustain attention in play activities.
* Seems not to listen to what is said to him or her.
* Fails to follow through instructions or to finish homework or chores (not because of confrontational behaviour or failure to understand instructions).
* Disorganised about tasks and activities.
* Avoids tasks like homework that require sustained mental effort.
* Loses things necessary for certain tasks or activities, such as pencils, books or toys.
* Easily distracted.
* Forgetful in the course of daily activities.
Hyperactivity
A child must have exhibited at least three of the following symptoms for at least six months to an extent that is unusual for their age and level of intelligence.
* Runs around or excessively climbs over things. (In adolescents or adults only feelings of restlessness may occur.)
* Unduly noisy in playing, or has difficulty in engaging in quiet leisure activities.
* Leaves seat in classroom or in other situations where remaining seated is expected.
* Fidgets with hands or feet or squirms on seat.
Impulsivity
At least one of the following symptoms must have persisted at least for six months to an extent that is unusual for their age and level of intelligence.
* Blurts out answers before the questions have been completed.
* Fails to wait in lines or await turns in games or group situations.
* Interrupts or intrudes on others, e.g. butts into others conversations or games.
* Talks excessively without appropriate response to social restraint.
A diagnosis is only given when the child is affected adversely in day-to-day situations. Being boisterous, lively or defiant are not acceptable diagnostic criteria.
My DD1 has ADHD traits, and the Learning Disabilities Nurse wants to have her formally assessed for ADHD. It won't make any difference to her education, because she already attends a Special school as she has a brain malformation. BUT
It is painful sometimes to watch a 4 year old girl physically clamp her hand over her mouth to stop the words getting out, because she has been told to 'wait' and she can't stop herself from talking.
I could go on, but it isn't what the OP has asked.
Here is a concentration excercises page, which states that children with ADHD can concentrate on tasks they find very interesting, but struggle with boring, repetitive tasks.
My DD1 has a concentration span of 30secs-2minutes for tasks, but can concentrate for over 20 minutes if she is using glue, or sand, which are highly tactile.