Personality disorders are some of the more challenging psychiatric conditions and have traditionally been viewed by many clinicians as more difficult to treat than numerous Axis I conditions, often requiring investment in more lengthy treatments that involve a variety of modalities and approaches. It is also common to attain lesser and more modest degrees of success in treating personality disorders, with a recognition, however, that even partial modifications in people's dysfunctional interpersonal relationships, coping mechanisms, and symptomatology can bring about notably better adaptations. Psychotherapy continues to be the treatment foundation for all personality disorders, and psychotherapy studies of personality disorders on the whole find that patients with these disorders improve with treatment, with large treatment effects—two to four times greater than the improvement found in the control conditions (Perry and Bond 2000). In more recent years, the traditional psychodynamic therapy approaches have become enriched with more eclectic possibilities and structured therapies, such as dialectical-behavioral therapy for borderline personality disorder (BPD) (Linehan 1993) and various other cognitive psychotherapies (Tyrer and Davidson 2000). Although medications continue to be an adjunct to the treatment of personality disorders, and research medication treatment trials in personality disorders continue to be much fewer than those available in Axis I disorders, medications undoubtedly can play a useful role in the treatment of personality disorders, at least in some disorders and for some patients.