Modern Narcissism and Buddhism

I was wondering if there were descriptions of Modern Psychological Narcissism in Buddhist works (as opposed to vanity in the Greek myth)? Is it closely tied to notions of Ego?

In buddhism, what suffering ISN'T a problematic tie to notions of ego?

Joking aside, the personality disorder constructs and buddhism have their own traditions of thoughts, and as as such one can find both similarities and differences in comparison. Your question is interesting, but also run the risk of confirmation bias, as long as one only look for buddhist concepts that fits with mental disorder diagnostics. I believe one may also find diverging concepts in comparing buddhism and personality disorders.

However, since your question actually pertains similarities, some things worth noting is the idea of unwholesome mental factors (akusala cetasikas) in buddhism.

Specific for the etiology of NPD (on the top of my head) is pretty much all of the unwholesome mental factors, with the possible exception of uddhacca (restlessness), kukkucca (regret), thīna (sloth) middha (torpor), or vicikicchā (doubt) which aren't necessary criterias for a NPD diagnosis per se.

Regarding BPD, i'd actually argue that the emotional shifts are only erratic or extreme for a layperson. I also believe that the dichotomous thinking associated with BPD is a bit of a overgeneralization, even though it can be prevalent among those diagnosed. I write this because people diagnosed with BPD run the risk of being burdened with A LOT of unfair misconceptions.

That aside, from a buddhist perspective i'd argue that akusala cetasikas that (arguably) fits with BPD are: moha (delusion), anottappa (disregard for consequence), lobha (greed), uddhacca (restlessness), ditthi (wrong view), or dosa (hatred). Again, these are in no way reserved for a BPD diagnosis specifically.

Looking at the buddhist idea of skandhas, one may argue that the emotional proclivites in BPD relies heavily on constitution (rupa), in conjunction with an unhealthy amount of negative life experiences. However, as far as i understand, buddhism doesn't rely too much on the impact of memories, and seeing past trauma and/or abuse as karma is rather cynical in my opinion.

On can also look at any form of mental disorder as matter of upadana or clinging. As we lose flexibility in dealing with life, mental illness is not seldom the result.

Are there teachings of Buddhism that could be especially helpful for such people?

A little buddhism would likely help a lot of people to improved well being, diagnosed or not.

Fact is that one of the evidence based treatments for people diagnosed with BPD (dialectical behavior therapy, or DBT) is influenced by zen buddhism, and one of the main figures - Marsha Linehan - claims to be a practicing zen buddhist as far as i understand. The treatment relies heavily on mindfulness practice, but there are also other ingredients involved in the treatment, some of which may be contrary to buddhist thought (the idea of emotional validation, or certain aspects of the interpersonal skills training for instance).

A lot more can be said about this, so consider my answer a scratch on the surface. Read it with a grain of salt.

There's a passage from the daodejing that I always find appropriate on questions like this. It goes, roughly:

When one man hears of the dao, he sets out to embrace it.
When another hears of the dao, he is interested, and thinks about it sometimes.
When a third hears about it, he laughs out loud at how silly it sounds.
If no one ever laughed at it, it wouldn't be the dao.

In order to appreciate the philosophy of Buddhism, we have to appreciate the problem of Buddhism: the problem of discontent and its cessation. And it isn't enough to appreciate the problem intellectually — in that, "Yeah, I know, a lot of people are miserable" sense — we have to feel the problem. We have to embrace the problem down in the core, because until we embrace the problem, we will have no reason to embrace the solution.

Not everyone can embrace the problem in this visceral way, and so we find a wide range of 'intellectual' Buddhists, who are quite devout (in their own way) but carry on a shallow practice. And we find other people who cannot even appreciate the problem intellectually, and write the philosophy off as mere farce. That is... what is.

When we talk about people with personality disorders, we are talking about people with (in general) a pervasive debility in both self-reflection and other-reflection. At best they make a mental beeline towards immediate gratification without considering secondary consequences; at worst they see the world as a zero-sum game of misery, where the more misery they inflict on others the less they think they will experience for themselves. Such people would have no interest in Buddhism (which they'd probably denigrate as 'sop for losers'). You couldn't get them to sit on the cushion without offering them some immediate, tangible reward (which would be counterproductive). I'm not saying it wouldn't be good for them in the long run — practice benefits everyone — but we'd have a job getting them to take the idea seriously in the first place.

I sometimes find it helpful to remind myself that we can't always help damaged people, but we can aim for a world that damages people less. That is (I think) the essence of the bodhisattva .