According to the Diagnostic and Statistical Manual of Mental Disorders, someone who exhibits 5 of the following 9 characteristics suffers from Narcisssistic Personality Disorder:

1.An exaggerated sense of self-importance (e.g., exaggerates achievements and talents, expects to be recognized as superior without commensurate achievements)

2. Preoccupation with fantasies of unlimited success, power, brilliance, beauty, or ideal love

3. Believes he is "special" and can only be understood by, or should associate with, other special or high-status people (or institutions)

4. Requires excessive admiration

5. Has a sense of entitlement

6. Selfishly takes advantage of others to achieve his own ends

7. Lacks empathy

8. Is often envious of others or believes that others are envious of him

9. Shows arrogant, haughty, patronizing, or contemptuous behaviors or attitudes