Hello,
One of the programs that our school is doing with some extreme students is what we call an Incremental Farm-out Program.
This program allows the student stays in the classroom for 15 minutes to begin with. Then the student is pulled out and reinforced for staying in the classroom and doing what is expected. As confidence builds so does time in class..The idea of maybe I can do this begins to develop in the students' thought. Then the next time the student remains to 30 minutes. I like the keep the students at this step for a while until they are at the point that they are saying, "If I leave I'll miss something"..well this is what we want of the student, and that is to be desiring knowledge.
The idea is that most students are so used to remaining in the classroom only until they act out. If we allow them to leave before they act out then they may realize that they do not need to act out to get what they want. Then gradually adding more classroom time so that they do not feel overwhelmed. This strategy has worked for several hard core students.