The Psychopath Detector

In romantic relationships, a psychopath may be charming and affectionate just long enough to establish intimacy with a partner, and then suddenly become abusive, unfaithful, and manipulative. The bewildered partner might turn to friends and family with their story, only to be met with disbelief—how could the warm, outgoing individual everyone has come to know possibly be guilty of these acts? All too often, the abused partner blames the situation on themselves, and comes out of the relationship emotionally destroyed.

The detector is a checklist within this GREAT article:
http://www.damninteresting.com/the-unburdened-mind