In our experience, it is patients with borderline or narcissistic personality disorder who present the most consistent difficulty for therapists. In a sense, these two groups of patients pose opposite dilemmas to therapists: Patients with BPD, are too needy and oversensitive for many therapists, whereas patients with narcissistic personality disorder are often not vulnerable or sensitive enough. Both groups are ambivalent about the process of therapy. As with our treatment of patients with BPD, our approach to patients with narcissistic personality disorder utilizes a mode-based approach. It was largely in order to treat these two types of patients more successfully that we developed the concept of modes. The mode approach allows us to build a therapeutic alliance with the parts of the patient that strive for health, while simultaneously fighting the maladaptive parts—those that move toward isolation, self-destruction, and harming others.