Personality disorders: a dimensional defense mechanism approach.

Categorical disease models of personality disorder currently dominate in the DSM-IV-TR and ICD-10 diagnostic systems. In preparation for DSM-V, these models have been questioned in light of evidence and widely held beliefs that disorders of personality are extreme variants of normal personality. Unfortunately, problems arise in trying to produce a dimensional model of abnormal and normal personality, such as how aspects of normal personality can be applied to personality disorders, and the all-important issue of precisely what aspect of normal personality is overextended in these disorders. In contrast to other approaches, a dimensional model based on defense mechanisms is easily applied to personality disorders, eliminates the need for complex scales, retains the notion of entities with which clinicians are familiar, provide useful therapeutic strategies, and clearly specify what aspect of normal personality is overextended. It also allows for the addition of new personality disorders.