personality disorder

People have an inflated sense of their own importance and a deep need for admiration. Those with narcissistic personality disorder believe that they're superior to others and have little regard for other people's feelings. But behind this mask of ultra-confidence lies a fragile self-esteem, vulnerable to the slightest criticism.

There is also the success oriented narcissist. She will be your friend and keep you close to her as long as you are useful. Once you do not have anything more to offer and she has taken all they wanted from you, you are history. You are no longer desired, wanted, or sought.

http://en.wikipedia.org/wiki/Echo_and_Narcissus