There are probably other causes of acting-out, and certainly there are other self-destructive manifestations of anger, but the following comments are derived from my tutoring of and therefore also life-coaching schoolboys from the 7th, 8th, 9th and 10th grades. In most cases, their acting-out in school was first officially commented on in or near the 4th grade, when they were 10 years old; i.e. still pre-pubertal. They were generally given a diagnosis of ADD/ADHD, and referred to a psychologist for behavior modification and to a psychiatrist for medication, usually a CNS stimulant such as Ritalin or Adderall. They also usually developed insomnia at about the same time.
Their parents referred the boys to me because they knew that I had been a professor of physics, and that I also used to teach in the science honors program given for bright junior high school and high school students Saturday mornings at Columbia University. I was nominally supposed to tutor them in math and science, but of course it evolved into life-coaching since their societal attitudes had to be adjusted by the students themselves, with some input from me. Remember that all of these boys had gone through nursery school in Bergen County, where they had learned to color within the lines, line up, be polite, follow orders, ask for permission, sit in their seats unless given permission to leave, etc. They also were in private school K-8 or 9-12, and the private school would never allow a boy who was obviously acting out in the interview, etc, to be admitted, so we know that they knew how to "behave"; it was just a matter of what they felt like doing in school and why. By the 7th grade it was obvious to everyone that the students were performing way below their abilities, as evidenced by the downward deviation from their previous scholastic levels, and I was asked to tutor/educate/motivate them. They were still being followed by psychiatrists or other therapists.
One common manifestation of their anger/acting-out was their handing in homework late, or incomplete, or not at all. The usual cognitive tricks such as asking the student to place the finished homework by the front door, or giving the parents a copy of the homework assignment never worked, because like the act of doing the homework itself, it required the active cooperation of the student. You know you can't make a two-year-old eat spinach if he is unalterably opposed to it and you also can't push on a rope. Either analogy will do. I had to help the students to understand that this negative behavior, although it made them feel better by "rebelling" only hurt them because they would be labeled as unreliable and undependable.
Another manifestation was that of doing poorly in tests, either by running out of time and not finishing the test, or leaving questions blank and unanswered. Like underperforming their homework assignments, they felt that they had demonstrated something by their actions. Again, I had to point out that all the teacher would note was (a) poor test results and (b) underperforming, and that this "rebellion" served little purpose since no one would understand or applaud their martyrdom.
All of these actions are, of course, examples of passive aggression, taken to the extreme. They all affected "la belle indifference" as a response to all the negative comments about their actions, as though they were above it all, and that it all was of little consequence in the long run and could not possibly affect their lives as grownups. The problem could not be solved by addressing their anger directly, because the anger was disconnected from their self-picture of reality.
Each student had to be convinced that the world at large didn't care if he was angry or unhappy, but was only interested in the results of his actions. They had to understand that actions or lack thereof did have consequences, and if a teacher labeled them as "unreliable", it would make their future lives quite difficult. They finally understood that their first recommendations come from their high school teachers, and that in these days of electronic records, once a comment was entered about their behavior or performance, be it good or bad, it would follow them for the rest of their lives, sort of like a scholastic Facebook.
I have come to the conclusion that parents have to explain to their pre-adolescents that actions and society's opinions of their actions do have long-term consequences. Yelling at the boys to do their homework or make their beds or pick up after themselves usually has little effect. Boys seem to enjoy whatever rebellion against society they can get away with , especially if it also draws attention to themselves. Of course now with cellphones, the boys all talk with each other and give each other advice as to how to "handle" their parents or school. It's not as serious as the website that teaches anorectic girls how to hide their anorexia, but there is always a subculture and a background current of which parents are (blissfully?) unaware.