My own pet theory of the relevant personality disorders is this: Narcissism and Boderline are extremes on the same scale, namely, how you manage your identity.
BPDs are "extreme followers" which seek whole systems of validation, identity and meaning from their local social environment. NPDs are "extreme leaders" which cannot receive this validation socially, so push-out a delusional theory of their own identity (, role, value system, etc.). -- Which is why, so often, the structure of a cult is one NPD leader and a coterie of BPD followers.
If this scale exists, ie., from follower-to-leader... then many conditions can influence your position on it. A "healthy" person is presumably one who, I'd say, is mostly a mild follower but will adopt a mild leader position when required (eg., by role).
In ASD, my guess is that since some social mirror / double-empathy /etc. is different/impair, you get NPD-like problems because you're not getting that social validation feedback signal, so you're having to push out some validation/identity/etc. system of your own.
Likewise in ADHD, you tend to find a lot of social rejection due to impulsive behaviours that alienate people.. so you get a comorbid BPD-ish quality where you're aware of the social validation available, but are constantly fighting your own impulsive undermining of receiving it.
One diagnostic difference between the ASD-ADHD vs. NPD-BDP categorisation should be the possibility of self-awareness, where in the former you'd expect improving self-awareness to have some immediate benefits -- but in the later, often none. Since position on the leader-follower line in ASD/ADHD is effectively an "ecological concequence" of repeated accidental behaviours, whereas in NPD/BPD its something stranger and I think less well understood. One imagines, most probably, very early infant trauma that has severely impaired psycho-social development.
BPDs are "extreme followers" which seek whole systems of validation, identity and meaning from their local social environment. NPDs are "extreme leaders" which cannot receive this validation socially, so push-out a delusional theory of their own identity (, role, value system, etc.). -- Which is why, so often, the structure of a cult is one NPD leader and a coterie of BPD followers.
If this scale exists, ie., from follower-to-leader... then many conditions can influence your position on it. A "healthy" person is presumably one who, I'd say, is mostly a mild follower but will adopt a mild leader position when required (eg., by role).
In ASD, my guess is that since some social mirror / double-empathy /etc. is different/impair, you get NPD-like problems because you're not getting that social validation feedback signal, so you're having to push out some validation/identity/etc. system of your own.
Likewise in ADHD, you tend to find a lot of social rejection due to impulsive behaviours that alienate people.. so you get a comorbid BPD-ish quality where you're aware of the social validation available, but are constantly fighting your own impulsive undermining of receiving it.
One diagnostic difference between the ASD-ADHD vs. NPD-BDP categorisation should be the possibility of self-awareness, where in the former you'd expect improving self-awareness to have some immediate benefits -- but in the later, often none. Since position on the leader-follower line in ASD/ADHD is effectively an "ecological concequence" of repeated accidental behaviours, whereas in NPD/BPD its something stranger and I think less well understood. One imagines, most probably, very early infant trauma that has severely impaired psycho-social development.