The term personality disorder encompasses a wide range of issues, each with a different level of severity or disability; thus, personality disorders can require fundamentally different approaches, understandings, and possible treatments. In this module, you learned about three different clusters and ten unique disorders: paranoid, schizoid, schizotypal, antisocial, borderline, histrionic, narcissistic, avoidant, dependent, and obsessive-compulsive personality disorder. It is evident that all individuals have a personality, as indicated by their characteristic way of thinking, feeling, behaving, and relating to others. For some people, these traits result in a considerable degree of distress and/or impairment, constituting a personality disorder. To be diagnosed with a personality disorder, the following criteria must be met:

• The individual has an enduring pattern of inner experience and behavior that deviates markedly from the expectations of the individual’s culture. This pattern is manifested in two (or more) of the following areas:
  • cognition (i.e., ways of perceiving and interpreting self, other people, and events).
  • affectivity (i.e., the range, intensity, lability, and appropriateness of emotional response).
  • interpersonal functioning.
  • impulse control.
• The enduring pattern is inflexible and pervasive across a broad range of personal and social situations.
• The enduring pattern leads to clinically significant distress or impairment in social, occupational, or other important areas of functioning.
• The pattern is stable and of long duration, and its onset can be traced back at least to adolescence or early adulthood.
• The enduring pattern is not better explained as a manifestation or consequence of another mental disorder.
• The enduring pattern is not attributable to the physiological effects of a substance (e.g., drug abuse or a medication) or another medical condition (e.g., head trauma).

A considerable body of research has accumulated to help understand the etiology, pathology, and/or treatment for some personality disorders (i.e., antisocial, schizotypal, borderline, dependent, and narcissistic), but not so much for others (e.g., histrionic, schizoid, and paranoid). However, researchers and clinicians are now shifting toward a more dimensional understanding of personality disorders wherein each is understood as a maladaptive variant of general personality structure, thereby bringing to bear all that is known about general personality functioning to an understanding of these maladaptive variants.