I am still learning everyday about this condition. I feel that the name itself should be changed. It is really not a "deficit" or a "disorder". The condition is a really "a heightened awareness" about everything. The person who has this condition really is able to "pay attention" but to everything at once. It is difficult to channel what to narrow their focus on.
To a child entering a primary grade classroom it is very hard to focus on the teacher because they are able to take in everything at one time. It is almost equivalent to being in a circus. Classrooms are often "too decorated" (colors, shapes, the alphabet, things hanging from ceilings, etc.) for these children to focus on any one particular thing. The medication assists in turning off some of these "extra senses".
Medication should not be started unless everything else has been ruled out. Some children have vision/hearing problems as well as discipline problems. If the child has very little structure prior to starting school they will have problems staying seated, on task, etc. It still may take several years for them to adjust to being seated and expected to complete tasks in a timely manner.
There is so much more that I feel about this but I am saving it for my dissertation one day.