Empirical research confirms clinical impressions that personality disorders are difficult to treat in psychotherapy. Personality pathology interferes with the therapeutic process, largely due to problems in alliance formation. Future models of treatment need to be built on a broader theory of the etiology of the personality disorders. These conditions are best understood as pathological amplifications of normal personality traits. The temporal stability of personality disorders can be accounted for by the genetic influence on these traits. Treatment involves helping patients to develop more adaptive ways of using their underlying traits.