Sociopathy or psychopathy (same thing) is not a psychosis. A psychosis is a break from reality, for whch the sufferer has no responsibility, and can be treated with drugs. Sociopaths have a personality disorder causing them, amoung other things, to like hurting others. They are responsible for thier actions - and just like doing evil. There is no known cure.
The second point you make varies with state law; if I'm not mistaken, some states wipe out juvinile fenonies, some don't. But I think the matter is more complex than even that, and it depends upon the kind of felony were talking about, and other factors.