Since the fragile ego of individuals with NPD is hypersensitive to perceived criticism or defeat, they are prone to feelings of shame, humiliation and worthlessness over minor or even imagined incidents.

Generally, the symptoms of NPD also impair the person's psychological abilities to function, either at work, or school, or important social settings.

The DSM-5 indicates that the traits manifested by the person must substantially differ from cultural norms, in order to qualify as symptoms of NPD.

Narcissistic personality disorder (NPD) is a personality disorder in which there is a long-term pattern of abnormal behavior characterized by exaggerated feelings of self-importance, an excessive need for admiration, and a lack of understanding of others' feelings.

Persons with narcissistic personality disorder (NPD) are characterized by their persistent grandiosity, excessive need for admiration, and a personal disdain for, and lack of empathy for other people.

True symptoms of NPD are pervasive, apparent in varied situations, and rigid, remaining consistent over time.

The NPD symptoms must be sufficiently severe to the degree that significantly impairs the person's capabilities to develop meaningful human relationships.The general move towards a dimensional (personality trait-based) view of the Personality Disorders has been maintained despite the reintroduction of NPD.The World Health Organization's (WHO) International Statistical Classification of Diseases and Related Health Problems, 10th Edition (ICD-10) lists narcissistic personality disorder under Other specific personality disorders.Also inherent in this process are the defense mechanisms of denial, idealization and devaluation.According to the DSM-5, "Many highly successful individuals display personality traits that might be considered narcissistic.These findings suggest that narcissistic personality disorder is related to a compromised capacity for emotional empathy and emotional regulation.