Narcissism is likely related to other addictions in that it is the result of some cognitive functions being missing so that the individual’s brain is run by the amygdala, on automatic. No learning/modification occurs. Poor Donald is addicted to a self he does not know.
There is a tendency to forget, probably because he continues to be surrounded by rational persons attracted to money, that poor Donald is still a narcissist. The narcissist is self-involved without having a sense of self. So, the self is a fiction, a fake. Such a person can, for example, perceive the relationship between an unrelated husband and wife as an occasion by either party of disrespect for himself. Inattention is an insult for which he is entitled to seek revenge. Thus, the defamation suit by one of his victims is a good start. There need to be many more, not because his verbal aggression is likely to be changed but because society has to establish a record that verbal abuse will not be tolerated. I have just been reading a manual by the bureau of prisons for inmates which starts out with the assertion that inmates, as well as all personnel are entitled to be treated with respect. Certainly, if we can insist on respect in our prisons, we can expect to find it in the society as a whole.
That said, the Donald does have a narcotic-like effect on his clients.