I don't know the extent of your early trauma, but I think we both share the fact that physical abuse was a part of our childhood.

I have a few significant factors contributing to my development. One, I was adopted at the age of three. So the first three years (memories consigned to my subconscious) were without any mother. Two, the parents who adopted me were both abusive and coddling. I was put in ice baths for punishment, and spanked with a belt regularly. This isn't nearly as extreme as it could have been (I wasn't neglected or severely beaten), but combined with feelings of abandonment from learning of my adoption around the age of 6, and being regularly bullied at school and around my neighborhood from the ages of 5-9 (because it was known I was adopted), I started taking things out on anything in my surroundings. Many of these shameful memories have deeply impacted me to this day.

Fortunately there were mitigating influences there too, healthy love from other relatives, music and art (scientifically proven to spur empathy in children), and early moral life lessons. These were things that I theorize may have destabilized an early chronic narcissism, rendering some features latent.

To be sure, the seeds for NPD defenses were there early. I can recall fabricating a persona in my childhood. But I oscillated between these states throughout my youth between parasitic and predatory behavior and moral compunctions, empathy and guilt. For example I may turn on distant friends or acquaintences (I never betrayed any close friends), or bully someone, but then feel overwhelmed by guilt later. Various empathy inducing events, and then NPD defense triggers colored a lot of my "rollercoaster" upbringing.

Interestingly, I was able to fall deeply in love with a girl in my early 20s. However narcissistic I was at the time, I know I would have unconditionally and altruistically given my life for her, which to my understanding doesn't exactly fit the NPD template. That ended very badly because she had been cheating, and my belief she would change turned into chance after chance until our relationship devolved into dysfunctional encounters (obviously I loved her and couldn't look the other way with her continuous cheating) Finally, after ignoring friends on this matter for some time, in the grips of a textbook emotional breakdown, I managed a tear soaked self-intervention, and was able to break up with her.

But the emotional and psychological fallout from that was unbearable. I count this among a few traumatic triggers (early 20s) or at least narcissism fortifying events that further cemented my NPD response. Having a longtime friend who was conspicuously high on the spectrum not be "available" for conversation that wasn't superficial didn't help during this very raw period. I couldn't get over her for years.

I markedly turned much further inward in the years following that breakup, becoming rigidly perfectionistic and more critical of others.

Whatever degree of psychopathy may or may not apply to you (it sounds more like you're describing 'sociopathy', which as it turns out is more innately empathetic than previously thought) you might be curious to know that like NPD, our understanding of psychopathy is changing too.
e.g. Psychopaths Can Feel Empathy Too, When They Try

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