Narcissism is a continuous personality trait—
Shocking News: We are all at least a little bit narcissistic. Think of this trait as a spectrum, similar to autism.
Good News: People, on average tend to become less narcissistic from young adulthood to middle age, with the magnitude of this decline being related to the particular career and family pathways a person pursues during their life.
Research shows that significant life events, like investing in a long term relationship, committing to family life, prosocial volunteering does change personality overtime. Yes, even in those diagnosed with narcissism.
Bottom Line: Commitments to things that take us outside of ourselves curbs narcissism. As we age, and gain life experience our personalities change. Yes, even a narcissist can become less narcissistic overtime.