I have had experience with at least two students. Schools do the best they can, and usually call in as much support as possible: parents, psychologist, social worker, superintendent, behavior resource people, and previous teachers.
In most cases, behavior plans are drawn up with consultation by all, including the child. There are rewards and consequences. There are reductions of expectations for the child, other than getting the behavior back on track. There is usually a number of discussions around reducing the anxiety or trying to find the triggers. This might take a form of tracking Antecedents, Behavior, Consequences, so that staff can analyze what might be causing the behavior.
But, if a child does not buy into any of these plans, and continues to disrupt the classroom, and often poisons the atmosphere, what is the next step?
There are administrative transfers to a new school to have a fresh start. This sometimes helps, as often relationships with peers and staff have broken down. I know that we have taken some children on this basis, and always try to have a clean slate, with some supports to reduce anxiety.
Schools try not to be punitive, contrary to what people think, especially if suspensions have been given. A suspension gives everyone some breathing space--a break from each other to recover. This is often needed for the child, the teacher and the rest of the class. It is stressful dealing with volatile behavior, or harsh words, and disrupted routines. Of course, a suspension is not easy on parents who are working, and the stress resulting from lost wages, or unscheduled absence from work can be difficult to manage. But, often the school does not have the personnel to remove the child from a class and provide supervision as an alternative.
What other ways have you used to deal with students who have not responded to interventions to normalize the school day?