SEATTLE - "I've been going through this since I was 11 years old," the young woman said, "I'm backed up against the wall. Either I need to do this therapy or I need to die." "Well, why not die?" the therapist asked. "Well, if it comes down to it, I will." "Uh-huh, but why not now?" This aggressive cross-examination is a signature technique of what has become one of the most popular new psychotherapies in a generation. For years, psychotherapists have had a wide array of techniques to draw from in helping troubled patients. The most commonly discussed recent therapies...