Eventually, the brain might mature as the psychopath ages. This may be why most serial killers are under 50. The abnormal brain wave activity comes from the temporal lobes and the limbic system of the brain, the areas that control memory and emotions. When development of this part of the brain is genetically impaired, and the parents of the child are abusive, irresponsible or manipulative, the stage is set for disaster. They don't want to change.
Most psychopaths end up in prison, instead of psychiatric hospitals.
Psychopaths identify with the aggressive role model, such as an abusive parent, and attack the weaker, more vulnerable self by projecting it onto others. The infant comes to expect that all outside experiences will be painful, and so he turns inward. The child refuses to identify with parents, and instead sees the parent as a malevolent stranger. Soon, the child has no empathy for anyone. The wall has been built to last.