What azjoe said, +1. Discipline works.
One success story (so far):
This past March my daughter calls me from Arkansas (where she lives). My Grandson (13 then) was not studying, and fighting in school so often that the school said the next time he goes to Juvenile Hall. She says, "He's uncontrollable, do you want him?" I drive to Arkansas and have papers notarized at the local small town courthouse.
Upon arrival back in Indiana I take him to school and give them permission to paddle him w/o asking me first (permission was needed before they could do it). I then, in his presence, gave each of his teachers a slip of paper with my phone number and instructions to call me regarding any problem whatsoever. So far, they have only called me 3 times. None of those calls were in the last 6 months. His grades went from C-F to A-C. His ability to read has increased exponentially, in 10 months he has went from "See Spot run" to adult level science fiction novels.
No, I do not paddle him myself (although I would not hesitate to). I use the exact same discipline methods that the U.S. Armed Forces use on all new recruits. Many recruits are, in fact, minors. My methods are therefore IMO "government approved". Works great. (He can also now do 4 times as many pull-ups and push-ups than anyone else in his class)
Get involved, it doesn't take much extra time... The results can be astounding.