Excerpt from Personality Disorders

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Background

A personality disorder, as defined in the Diagnostic and Statistical Manual of the American Psychiatric Association, Fourth Edition, Text Revision (DSM-IV-TR), is an enduring pattern of inner experience and behavior that differs markedly from the expectations of the individual's culture, is pervasive and inflexible, has an onset in adolescence or early adulthood, is stable over time, and leads to distress or impairment. Personality disorders are a long-standing and maladaptive pattern of perceiving and responding to other people and to stressful circumstances. Ten personality disorders, grouped into 3 clusters (ie, A, B, C), are defined in the DSM-IV-TR.¹

Pathophysiology

The origin of personality disorders is a matter of considerable controversy. Traditional thinking holds that these maladaptive patterns are the result of dysfunctional early environments that prevent the evolution of adaptive patterns of perception, response, and defense. A body of data points toward genetic and psychobiologic contributions to the symptomology of these disorders; however, the inconsistency of the data prevents authorities from drawing definite conclusions.

Frequency

United States

Personality disorders affect 10-15% of the adult US population. Individuals may have more than one personality disorder. The following are prevalences for specific personality disorders in the general population:²

• Paranoid personality disorder - 0.5-2.5%
• Schizotypal personality disorder - 3%
• Antisocial personality disorder - 3% of men, 1% of women
• Borderline personality disorder - 2%
• Histrionic personality disorder - 2-3%
• Narcissistic personality disorder - Less than 1%
• Avoidant personality disorder - 0.5-1%
• Obsessive-compulsive personality disorder - 1%

International

Because the DSM-IV-TR criteria are so bound to North American cultural definitions, epidemiologic data about personality disorders in other countries are notoriously unreliable.

Mortality/Morbidity

Patients with personality disorders are at higher risk than the general population for many (Axis I) psychiatric disorders. Mood disorders are a particular risk across all personality diagnoses. Some comorbidities are more specific to particular personality disorders and clusters.

• Cluster A: Paranoid personality disorder may appear as a prodrome to delusional disorder or frank schizophrenia. These individuals are at risk for agoraphobia, major depression, obsessive-compulsive disorder, and substance abuse. Individuals with schizoid personality disorder may develop major depression. Patients with schizotypal personality disorder may develop brief psychotic disorder, schizophreniform disorder, or delusional disorder. At the time of diagnosis, 30-50% have concurrent major depression, and most have a history of at least one major depressive episode. For more information, see Medscape's Schizophrenia Resource Center.
• Cluster B: Antisocial personality disorder is associated with a risk for anxiety disorders, substance abuse, somatization disorder, and pathological gambling. Borderline personality disorder is associated with a risk for substance abuse, eating disorders (particularly bulimia), and posttraumatic stress disorder. Suicide is a particular risk in borderline patients. Histrionic personality disorder is associated particularly with somatoform disorders. People with narcissistic personality disorder are at risk for anorexia nervosa and substance abuse as well as experiencing depression. For more information, see Medscape's Anxiety Disorders Resource Center.
• Cluster C: Avoidant personality disorder is associated with anxiety disorders (especially social phobia). Dependent personality disorder carries a risk for anxiety disorders and adjustment disorder. People with obsessive-compulsive personality disorder may be at risk for myocardial infarction because of their common type A lifestyles. They may also be at risk for anxiety disorders. Notably, they are probably not at increased risk for obsessive-compulsive disorder.

Race

No differences in prevalence across the races have been noted.

Sex

• Cluster A: Schizoid personality disorder is slightly more common in males than in females.
• Cluster B: Antisocial personality disorder is 3 times more prevalent in men than in women. Borderline personality disorder is 3 times more common in women than in men. Of patients with narcissistic personality disorder, 50-75% are male.
• Cluster C: Obsessive-compulsive personality disorder is diagnosed twice as often in men than in women.

Age

Personality disorders generally should not be diagnosed in children and adolescents because personality development is not complete and symptomatic traits may not persist into adulthood. Therefore, the rule of thumb is that personality diagnosis cannot be made until the person is at least 18 years of age. Because the criteria for diagnosis of personality disorders are closely related to behaviors of young and middle adulthood, DSM-IV-TR diagnoses of personality disorders are notoriously unreliable in the elderly population.

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