Introduction to Personality Disorders

Prevalence estimates for any personality disorder is 9.1%, with Cluster A personality disorders at 5.7%, Cluster B at 1.5%, and Cluster C at 6%. The prevalence for any personality disorder ranges from 9%-15%.^[1][2]

The prognosis of a personality disorder depends on the specific personality disorder. For example, antisocial and borderline personality disorder tends to improve or self-extinguish with age. Other personality disorders, like obsessive-compulsive personality disorder and schizotypal personality disorder are less likely to remit over time.

• Personality disorders are highly co-morbid with other personality disorders, and there is high overlap between the different clusters.

Personality traits are an enduring, repetitive pattern of perceiving, relating to, and thinking about the environment and oneself. Personality traits are not disorders.

The diagnosis for a general personality disorder is as follows (refer to a specific personality disorder for more specific criteria):

An enduring pattern of inner experience and behavior that deviates markedly from the expectations of the individual's culture. This pattern is manifested in 2 (or more) of the following areas:

1. Cognition (i.e - ways of perceiving and interpreting self, other people, and events)
2. Affectivity (i.e. - the range, intensity, lability, and appropriateness of emotional response)
3. Interpersonal functioning
4. 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. - a drug of abuse, a medication) or another medical condition (e.g. - head trauma).

• Whenever diagnosing a personality disorder, the clinician must consider the ethnic, cultural, and social background of the individual. Personality disorders should not be confused with problems associated with cultural adaption following immigration or with the expression of habits, customs, or religious and political values by the individual's culture of origin.
• Certain personality disorders, such as antisocial personality disorder) are diagnosed much more frequently in males. Others personality disorders, such as borderline, histrionic, and dependent personality disorders are diagnosed more frequently in females. Although this may reflect true differences in prevalence between genders, it is important to not overdiagnose or underdiagnose personality disorders because of social stereotypes about typical gender roles and behaviors.

• Personality change due to another medical condition
  • When personality changes occur due to the physiological or neuropsychiatric effects of another medical condition (e.g. - a traumatic brain injury or brain metastases), this diagnosis should be used instead.
• Other mental disorders and personality traits
  • Many of the criteria for personality disorders also describe features (e.g. - suicidal behaviour, suspiciousness, constricted affect, impulsivity) that are similar to other mental disorders. Thus, a personality disorder should be diagnosed only when the features appeared before early adulthood, are typical of the individual's long-term functioning, and do not occur exclusively during an episode of another mental disorder. It can be difficult to distinguish personality disorders from persistent mental disorders such as persistent depressive disorder that have an early onset and an enduring, relatively stable course. Other personality disorders can also exist on a spectrum or continuum of symptoms in relation to other mental disorders:
    • Avoidant personality disorder with social anxiety disorder
    • Schizotypal personality disorder with schizophrenia
  • Personality disorders must also be differentiated from personality traits that do not reach the threshold for a personality disorder. Personality traits only become a disorder when these features becoming inflexible, maladaptive, and persistive, and cause significant functional impairment or subjective distress.
• Psychotic disorders
  • For the cluster A personality disorders (paranoid, schizoid, and schizotypal) that may be related to the psychotic disorders, there are exclusion criterion that require the pattern of behaviors to not have occurred exclusively during the course of schizophrenia, a bipolar or depressive disorder with psychotic features, or another psychotic disorder.
• Posttraumatic stress disorder (PTSD)
  • When personality changes emerge and persist after an individual has been exposed to extreme stress or trauma, a diagnosis of PTSD should be considered.
• Anxiety disorders
  • One should be cautious about diagnosing personality disorders during an episode of an anxiety disorder, because these disorders can mimic personality traits on cross-sectional observation.
• Depressive disorders
  • One should be cautious about diagnosing personality disorders during an episode of a depressive disorder, because these disorders can mimic personality traits on cross-sectional observation.
• Substance use disorders
  • In individuals with a substance use disorder, a personality disorder diagnosis should not be made based on behaviors stemming from a substance intoxication or withdrawal. Additionally behaviours (e.g. - antisocial behavior) that are associated with perpetuating substance use should not be used to make the diagnosis of a personality disorder.