Statistics on Borderline Personality Disorder can be hard to come by. But reliable estimates indicate as many as one in fifty Americans may suffer from the disorder. It was first recognized in the 1930s, but therapists still argue over how to define and treat it. In fact, many object to the name itself, since personality disorders are often seen as less "serious" than the major mental illnesses like schizophrenia, depression, and bipolar disorder.This week on The Infinite Mind, we learn about the symptoms of BPD, why it is so frustrating for therapists to treat it, and a new form of therapy that has been effective.