It's entirely normal and healthy to be a little self-involved from time to time. But for some individuals, a preoccupation with the self can become excessive, impacting daily life and relationships in pathological ways. Narcissistic personality disorders are rare , yet their traits have long fascinated scientists. Despite decades of research, it remains unclear what causes a grandiose view of the self and a strong sense of entitlement, whether it be family history, early childhood experiences,