Blarg,
Countless resources on the net at various levels of academic/science-speak, but this looks like a pretty good relatively layman's term overview of all sorts of psychiatric disorders:
http://www.merck.com/mmpe/sec15.html
From Personality Disorders section:
"Narcissistic personality involves grandiosity. Affected people have an exaggerated sense of superiority and expect to be treated with deference. Their relationships are characterized by a need to be admired, and they are extremely sensitive to criticism, failure, or defeat. When confronted with a failure to fulfill their high opinion of themselves, they can become enraged or seriously depressed and suicidal. They often believe others envy them. They may exploit others because they think their superiority justifies it."