A person with narcissistic personality disorder:
Personality disorders are diagnosed based on a psychological evaluation and the history and severity of the symptoms.
Moore DP, Jefferson JW. Narcissistic personality disorder. In: Moore DP, Jefferson JW, eds. Handbook of Medical Psychiatry. 2nd ed. Philadelphia, Pa: Mosby Elsevier; 2004: chap 140.
Young JQ. Narcissistic personality disorder. In: Ferri FF, ed. Ferri's Clinical Advisor 2008: Instant Diagnosis and Treatment. 1st ed. Philadelphia, Pa: Mosby Elsevier; 2008.