Each medication has its strong and weak points, so many times it is a bit of a trial and error approach to see which one best fits the needs of the person. But medication alone is never the answer (if it is even needed). There really is a lot involved. If you have any more questions, please feel free to post on the ADHD site -
http://www.medhelp.org/forums/ADD---ADHD/show/175
By the way, if focusing is the issue (and it is not a recent occurrence), then it could be ADD. In the ADD situation, obedience is typically not a problem, and for that reason will go unnoticed by the schools.