Here is a pretty good definition of a narcissistic pathological liar (ignore the reference to politics).
http://drsanity.blogspot.com/2009/05...lying-and.html
From my observations of the trial, I do feel this is what Casey Anthony suffers from. However, this does not lessen what has happened to her daughter. First degree murder, in my opinion, should not even be a consideration. Aggravated manslaugter does sound plausible.
It's very sad that someone in her family didn't recognize Casey's behaviorial disorder before any possibility of escalation to a child's death occurred.... very sad.