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Day # 128: Introduction to Personality Disorders and Personality Clusters

If you are following along in the suggested curriculum you have now finished the first nine themes (psychotic disorders, depressive disorders, bipolar disorder, anxiety disorders, emergency psychiatry, OCD and related disorders, trauma/stressor related disorders, dissociative disorders, and psychosomatic disorders). Nice work!

We will now begin the tenth theme in the Bullet Psych curriculum which is personality disorders. Today we will provide a brief overview of these disorders and in the coming posts we will cover each disorder in detail.

Today's Content Level: Beginner; Intermediate (Review)


  • Personality is an individuals stable, predictable, emotional, and behavioral traits. It refers to all of the characteristics that adapt in unique ways to ever-changing internal and external environments. Personality can vary widely and many people have eccentric quirks and unconventional tendencies, however these are not pathological unless they impair daily function or cause significant distress.

  • Personality disorders are described as pervasive, maladaptive, and chronic patterns of behavior, thinking, and feeling, which ultimately lead to distress and dysfunction. These enduring patterns of behavior and emotional experience differ markedly from expectations of an individual's culture. Dysfunction may been seen in social, relational, or occupational areas and are especially vulnerable to developing symptoms of other mental disorders during stress.

  • In general, personality disorder symptoms are considered ego syntonic (as opposed to ego dystonic) and alloplastic. Ego syntonic = thoughts, behaviors, wishes, impulses are acceptable to the ego. Alloplastic = adapt by trying to alter the external environment or other people rather than themselves.


  • The World Health Organization has estimated the prevalence of having a personality disorder to be 6.1%. The prevalence of the three separate clusters (A, B, and C) is 3.6%, 1.5%, and 2.7%, respectively. See below for more info on personality clusters.

  • A number of biological, genetic, psychosocial, and cultural factors during childhood and adolescence contribute to the development of personality disorders. Risk factors for personality disorders include adverse childhood events, younger adults, unmarried, lower socioeconomic status, and lower education level. The precise etiology of personality disorders is unknown, but there are a broad range of theories.

  • Psychoanalysts traditionally suggest these disturbances result from a failure to progress through proper psychosexual development.

  • More recently, researches have found genetic correlations and genes of interest. The best evidence that genetic factors contribute to personality disorders comes from large twin studies. The prevalence of some personality disorders in monozygotic twins is several times higher than in dizygotic twins and monozygotic twins reared apart are about as similar as monozygotic twins reared together.

  • Personality disorders are a predisposing factor for other psychiatric disorders such as mood disorders, anxiety disorders, substance use disorders, impulse-control disorders, eating disorders, and suicide.


Enduring pattern of behavior/inner experience that deviates from the person’s culture and is manifested in ≥2 of the following ways:

  • Cognition (interpretation of self, other people, and events)

  • Affect (lability, intensity, and range of emotional responses)

  • Personal relations (interpersonal functioning)

  • Impulse control

  • Mnemonic -> CAPRI

The personality pattern:

  • is pervasive and inflexible in a broad range of situations

  • is stable and has an onset no later than adolescence or early adulthood

  • leads to significant distress or dysfunction

  • is not accounted for by another mental/medical illness or by use of a substance


Personality disorders are divided into three clusters based on certain shared features. Each personality disorder will be discussed in detail in subsequent lessons.

Cluster A

  • Disorders: schizoid, schizotypal, and paranoid

  • Group similarities: eccentric, peculiar, or withdrawn

  • Mnemonic: "cluster Abnormal" (the weird)

  • Prevalence: 3.6%

  • Familial association: psychotic disorders. More common in biological relatives of patients with schizophrenia. Strongest correlation with schizotypal personality and less correlation with paranoid or schizoid personality.

Cluster B

  • Disorders: antisocial, borderline, histrionic, and narcissistic

  • Group similarities: emotional, dramatic, or inconsistent

  • Mnemonic: "cluster Bloated" (the wild)

  • Prevalence: 1.5%

  • Familial association: mood disorders. More common in biological relatives of patients with depression (particularly borderline personality) and substance use disorders (particularly antisocial personality). Additionally, a strong association is found between histrionic personality and somatic symptom disorders.

Cluster C

  • Disorders: avoidant, dependent, and obsessive-compulsive

  • Group similarities: anxious or fearful

  • Mnemonic: "cluster Concerned" (the worried)

  • Prevalence: 2.7%

  • Familial association: anxiety disorders. More common in biological relatives of patients with anxiety disorders. Patients with avoidant personality often have high anxiety levels themselves. Obsessive-compulsive traits are associated with anxiety and depressive disorders.


  • Other specified / unspecified personality disorder: includes characteristics of a personality disorder that do not meet full criteria for any of the other personality disorders.

  • Personality change due to another medical condition: this refers to persistent personality change due to the direct result of a medical condition such as stroke, epilepsy, head trauma, or central nervous system tumors or infections. Subtypes include labile, disinhibited, aggressive, apathetic, or paranoid.


This post should be a review for intermediate learners, but hopefully this provided a helpful overview of personality disorders for beginners. Next post we will start with cluster A personality disorders and discuss paranoid personality disorder in detail.

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