[header] How to diagnose narcissistic personality disorder [title] Look for extreme self-importance. [step] People with narcissistic personality disorder think very highly of themselves in a way that crosses over the line of normal self-confidence. If you suspect that someone you know has this disorder, pay attention to how the person seems to think about him or herself and whether these feelings are grounded in reality. 
[substeps] The person may have obsessive fantasies about his or her own greatness. The person may lie about or exaggerate achievements in order to seem more accomplished.