Hi, It sounds like your son is extremely impulsive and aggressive toward his family, teachers, and peers. In situations where the aggressive behavior can seriously harm other people, I would recommend a residential school. I assume the behaviors you describe have occurred since he came back home from residential treatment. If so, it sounds like he was released too soon. There ought to be continual supervision and a very structured environment that only a residential placement can provide. Was there improvement while he was in that setting previously?
The change in moods sounds dramatic. He can go from gentle and caring to extremely aggressive and dangerous toward others. I would not rule out pediatric bipolar disorder, but I cannot make a diagnosis without being there to evaluate your son. I describe some of the criteria for pediatric bipolar disorder in my earlier books: "Your defiant child: Why is nothing working?" and "Why is my child's ADHD not better yet?" If bipolar disorder is present, appropriate medication should be considered.
Also you would want to rule out post traumatic stress disorder (PTSD) and fetal alcohol syndrome (FAS). The former can be caused by being exposed to violence or sexual abuse, and the latter is caused by being exposed to large amounts of alcohol in utero. FAS children can have extremely poor self-control, and it can take years to make small gains. For PTSD children, there is a range of functioning, depending on the abuse and on the child's make-up, but intensive therapy can often help.
In terms of behavioral treatment for your child, adults would need to intervene as quickly as possible when he gets angry, and be prepared to use physical restraints if people's safety is threatened. Usually ignoring outbursts is indicated, but not when someone could be seriously hurt. If some triggers are known, adults should try to avoid them or prepare your child in advance each time a known trigger might occur. Some other ideas are to establish distractions that are highly engaging for your child, and to go over "catch phrases" every morning before school like "Sometimes I'm not going to like the way other kids ask questions or play games. No one is perfect. Turn away if I don't like something." These possible cues are in response to the triggers you mentioned in the first paragraph of your e-mail. These and other approaches are outlined in my workbook on anger overload. Keep in mind that any of these behavioral approaches will not yield immediate results, especially if there is a mood disorder or other serious underlying diagnosis.
I would also recommend having your son evaluated at a major teaching hospital mental that is known to work with severe behavior problems and is aware of the kinds of mood disorders that can occur in children. Best, Dr. Dave Gottlieb