One of many on this topic: https://www.thoughtsonlifeandlove.com/the-difference-between-narcissism-and-autistic-spectrum-disorder-asd/
From the list of Effects, I cannot understand why Narcissism would be popped on to the Spectrum as it presents as a NT Psychotic. According to research I've been diving into for the last 6 years, these 2 categories exist: ND or NT, though 1. it's not Black and White but 2.these are based on specific variables, and I persoanlly would add 'Capitalist' into NeuroNormative A.K.A. NeuroTypical.
According to ongoing research (from Felix Guattari to Franchesca Happe) in extreme cases each can become or tend toward:
Schizophrenic < NeuroDivergent OR NeuroTypical > Perverse / Psychotic
other research I've found has suggested the Shizophrenic is in a Defensive Mode where the Psychotic is in an Offensive Mode. Both are in a very intense state of survival.
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I've occasionally encountered individuals with this bullet-like fist-pounding demand for truth. Arrogant, dismissive, but info-duming BUT with that spaced out sensory overload pause autistics can be happily guilty of. That sort of rebooting checked out vacancy that feels refreshing and spooks NTs out a bit. They seem driven but not always present. And wildly wrong in rather presumptous ways... I cannot make sense of these sort of individuals and I would like to for a matter of safety. I encounter them occasonally. Of course I went through times where I was naive, driven, intense, a bit much, not communicating or taking in language correctly, but was always grateful for advice or correction even if it was a painful or difficult process. One thing that held back the abilty to just learn and grow was feeling unprotected and fighting to just survive.
As someone who has been analytical since I can remember, I like knowing what I'm working with or getting into before I commit. I don't like surprises or making promises I cannot keep. Therefore always making fine adjustements, fine-tuning, corrections, re-design, re-orderings - essentially being 'open' is how I establish a sense of centring. And feeling grounded on a chaotic planet is primary. The last thing I would like to do is trip over 'my (insufficient) truth'.
I also don't want to use a term like this frivolously. Individuals can call themselves 'Spetrummy' but it doesn't carry the weight or judgement of Narcissism.
The bottom line is, with Autism still in a nebulous phase of research, when things get muddled up, the wrong representation can cost jobs. Errors in judgment from misrepresentations create very grave consequences.