And the question is! :)
My daughter was like that. She came to live with me as a foster child when she was 7 and had good reason to be extremely angry. She was in therapy nearly all of the time. At that time they didn't give drugs to someone that young. When she reached her teen years they did start trying various drugs but none of them really seemed to help until she was an adult and diagnosed her as being bi-polar. Even then it takes close monitoring and changing her meds from time to time. She is now living a successful life with 2 children and her anger mostly under control. But she does still have difficulties and always will.
She has told me all along that she doesn't remember her extremely angry words and actions towards me. A therapist told me that is probably true. She doesn't black out. She blocks out the painful. What she has said and done does not fit with who she believes that she is. If she were to remember and admit to what she's done she would feel like she's such a bad person she doesn't deserve to live. I've seen that happen with her. The not remembering is a coping mechanism that allows her to live a somewhat normal life in between the rages.
If he's a zombie he may very well be overmedicated. At the same time it takes a few weeks for his body to adjust so that he isn't a zombie. It took a couple of years for my daughter and her doctor to find the right combination of drugs. And she did feel drugged out whenever she started a new one or a new combination.
I've never heard of too much adrenalin causing blackouts. What I've seen is rage that won't stop. Adrenalin gives us energy and keeps all of our systems working at peak power. Usually we do then become quite fatigued and need to sleep afterwards. I've seen adrenaline rages that were fed by drugs such as speed (amphetimines) Those are different and can end with what looks like a black out. What happens is that the body can no longer function at that level and organs stop working. This sometimes results in death. That does not sound like what is happening with your nephew.
Who is the adult responsible for your nephew? It sounds like neither you or your step-mom have talked with the psychiatrist. I would not recommend going to a different one until you have personally determined that the one he has is not appropriate. I can't emphasize enough that finding a treatment that works takes a long time, perhaps years if he is bi-polar. Even without being bi-polar it still takes a long time. Each brain chemistry is different and reacts differently to drugs.
And this is also a case in which too many cooks will spoil the broth. All of you who are involved with him need to be consistently doing the same thing. And I can tell you from experience gained with a lot of teens that there is nothing that you can tell him that will directly help him change. He needs reassurance that you love him no matter what he does. That you don't approve of some of his actions but that you do love him. Accepting him as he is is very difficult.
I agree that it may help to get him involved in some activities. I doubt that meditation will help. He has too much energy fueled by his anger for that. But any of the marshall arts could help him. I've read recommendations for participating in marshall arts to learn how to control anger. At first that seems wrong but when you think about it the marshall arts are very disciplined. And they allow you to act out your aggression in a way that does not hurt anyone.
Hang in there and be supportive of whomever is raising him. Ask questions. Do research. The psychiatrist or psychologist could recommend some reading. These will be tough years but he will grow up and with the right psychiatric care be OK.
