Personality Disorders

Personality disorders (PDs) are defined in the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5; published by the American Psychiatric Association in 2013) as “an enduring pattern of inner experience and behavior that deviates markedly from the expectations of the individual’s culture, is pervasive and inflexible, has an onset in adolescence or early adulthood, and leads to distress or impairment” (p. 645). Although broad in scope, this definition is meant to distinguish PDs from other psychological disorders that are less clearly related to enduring personality. Indeed, as of 1980, in DSM-III, PDs were introduced in a different “axis” from other disorders, such as mood or anxiety disorders, ensuring that clinicians pay attention to acute disorders as well as personality-based problems in living. The former were classified under Axis I, or “Clinical Disorders,” representing acute manifestations of illness (e.g., schizophrenia, panic disorder), whereas PDs were classified under Axis II (along with mental retardation) in order to capture inflexible personality traits that have become problematic and that require psychological attention. However, with the publication of DSM-5, the multi-axial system has been eliminated in favor of a general scheme that places all disorders (clinical and personality) on the same diagnostic plane. In DSM-5, ten distinct PDs are listed, organized into three clusters: odd or eccentric (paranoid, schizoid, schizotypal); dramatic, emotional, or erratic (antisocial, borderline, narcissistic, histrionic); and anxious or fearful (avoidant, obsessive-compulsive, dependent) disorders. Individuals who show broad dysfunctions in personality that warrant treatment but who do not meet criteria for any specific PD are often classified as “Unspecified Disorder,” which is not in itself a personality disorder, but instead used to enhance specificity of an existing disorder or as a means of attaching a diagnosis to an individual for treatment purposes. Furthermore, a dimensional model of personality disorder, in which symptoms would be identified on a gradient scale of severity rather than a diagnostic checklist, was proposed during the DSM-5 revision process; however, this model was not approved to replace the categorical schema and was instead placed in section III of the manual (entitled “Emerging measures and models”). As of the early 21st century the etiology for PDs is unclear and multidetermined, but specific temperamental (e.g., neuroticism, disinhibition), environmental (e.g., childhood abuse), and biological (e.g., prefrontal cognitive control systems) factors have been most implicated. Specific etiological factors studied in regard to the three PD clusters as well as treatment approaches are reviewed in subsequent sections, with a focus on empirical and scientifically grounded publications.