Narcissism is either a birth defect which means their brains do not have the structures in order for them to become fully functional humans with depth and breadth of emotional understanding and control, or their brains and development become damaged due to trauma in childhood. Either way, they get stuck emotionally at a very low level of emotional development—toddlers with adult intellects and bodies. Toddlers throw temper tantrums to get what they want. But they can also be very sweet and snuggly when they are comfortable and all their needs have been met. The adult toddler is, unfortunately, harder to satisfy and therefore more prone to tantrums.
All humans can choose our behavior. I am not making excuses for an abusive person to behave abusively, and I’m not saying that an abuse victim needs to stay in an abusive relationship because their partner is suffering from a deformity. Narcissists behave abusively because it gets them what they want and need and because they have been allowed to get away with it. The behavior is a choice; they know who they can get away with abusing and when they can get away with it.
For example, I have a relative in an abusive relationship. Their spouse abused them in front of me and in front of mutual friends for years before I got sick of seeing it and went no-contact. The abusive spouse will abuse my sibling in front of the abuser’s parents, but has never abused my sibling in front of our parents. They know when and where and how they can get away with it. So it’s not that they are helpless victims of their disorder. They are very calculated and their behavior is absolutely their choice. Abuse is just the easiest and most satisfying way for narcissists get what they feel they need.
Editing to add: Posts tagged 'quora' were originally my answers to peoples' questions on quora.com. They were monetized but I am giving them away for free here.
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