Found this an interesting article, sums up Skankerella and quantifies theories and facts discussed:
Is narcissism a choice?
Narcissism is not a choice. It develops in early childhood when a person's personality is forming. Narcissistic Personality Disorder (NPD) comes from severe and long-term neglect, abuse, and hurt during upbringing. The neglect is so intense that the child creates an "alter ego" to protect themselves. This alter ego helps reduce the damage from the abuse, but emotionally, the child stays underdeveloped.
As a way to protect this alter ego, the ability to feel empathy disappears. Feelings that help protect the narcissist, like grandiosity (thinking they are the best or smartest) and entitlement, become stronger.
However, this new identity is fragile. Beneath the surface, the narcissist is weak, scared, and full of guilt and shame. They don’t feel worthy of real relationships based on love, friendship, and respect.
NPD is considered very difficult to treat because the narcissist’s entire identity depends on this alter ego. The narcissist believes they are the person their NPD has created. They don't remember becoming a narcissist, and to them, their narcissism is everything. Without it, they would have continued to feel neglected and abused. In their mind, narcissism saved them, making them feel "wonderful" and "successful."