Personality disorder clusters

Personality disorder clusters are one way of categorizing conditions that are among the most complicated psychiatric problems. People with personality disorders display a deep-seated pattern of maladaptive thinking and emotional instability that frequently leads to odd and erratic everyday functioning. Here are some important elements of personality disorders and categorizations of personal disorder clusters that every clinician needs to know. 

What is a personality disorder? 

Personality disorders exhibit a stable, pervasive, and inflexible set of characteristics that cause significant distress. They have at least two of the following four defining features:

The four core features of personality disorders

• Distorted thinking patterns. Faulty cognitions are a defining factor of many disorders and personality disorders are no different. The thinking errors can be severe and enduring. For example, the thinking of an individual with a paranoid personality is nothing short of delusional.   

• Problematic emotional responses. Reactivity is something you hear a lot about personality disorders. People with personality disorders may have emotional reactions that do not fit the situation. Think about the theatrical responses, for instance, of a person with histrionic personality disorder. 

• Impulse control problems. Many people with personality disorders are considered impulsive in their actions, while others are considered overly inhibited. A person with antisocial personality disorder, for example, may resort to reckless and risky behavior while someone with avoidant personality disorder may be afraid to attempt anything outside their comfort zone. 

• Interpersonal difficulties. People with personality disorders often have poor relationships with others. Think about how difficult it must be for another person to understand and cope with the extremes of someone with borderline personality disorder. Or the apparent indifference of someone who is schizoid. It can be very frustrating to try and have a close relationship with someone with a personality disorder. 

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Personality disorder clusters

According to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5TR), there are 10 kinds of personality disorders. These are categorized into three personality disorder clusters, based on similar characteristics. 

Personality disorder Cluster A

A person with a cluster A personality disorder tends to exhibit odd and eccentric behavior.

The following diagnoses are included in this cluster:

• Paranoid personality disorder
• Schizoid personality disorder
• Schizotypal personality disorder

Personality disorder Cluster B

A person with a Cluster b personality disorder displays dramatic and unstable behavior.

The following disorders are included in personality disorder cluster B:

• Borderline personality disorder
• Antisocial personality disorder
• Narcissistic personality disorder
• Histrionic personality disorder

Personality disorder Cluster C

An individual with a Cluster C personality disorder exhibits anxious and inhibited behavior.

The following diagnoses are included in personality disorder cluster C:

• Dependent personality disorder
• Avoidant personality disorder
• Obsessive-compulsive personality disorder

How common are personality disorders and personality disorder clusters?

It is estimated that nine percent of the US population has a personality disorder of some kind. The most common personality disorder is obsessive-compulsive personality disorder. 

Note: Personality disorders are not usually diagnosed in children because it cannot be determined whether they are enduring because of a child’s short lifespan and developmental changes. 

Can people with personality disorders be cured?

While professionals may be reluctant to say unequivocally that a personality disorder can be cured, they are definitely treatable. These disorders, however, are pervasive and ingrained, making care more difficult. What’s more, people within certain personality disorder clusters may shun treatment. For example, an antisocial person or someone with schizotypal personality disorder is unlikely to seek or maintain therapy. 

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Is treatment for personality disorders covered by insurance?

Let’s be honest: insurance companies do not like to cover treatment for personality disorders. Why, you may ask? Because personality disorders are difficult to treat and it is likely to take a long time. As clinicians, you may have to be creative when documenting reasons for treatment. Most people with personality disorders have associated problems that will readily be covered by insurance. For example, individuals with borderline personality disorder often have co-occurring depression or anxiety, illnesses easily accepted by insurance companies.  

How do we assess personality disorders?

Personality disorders are complicated to diagnose. A quick screening measure or unstructured interview is unlikely to yield the full picture necessary for an accurate assessment. Instead, it is recommended that clinicians primarily rely on scientific measures with proven reliability and validity. 

Structured clinical interviews for clients within personality disorder clusters

Structured interviews ask questions that tease apart the complexities of personality disorders. The Structured Clinical Interview for DSM-5 Personality Disorders (SCID-5-PD) is a popular and effective tool. It asks questions specifically related to diagnosing personality disorders as presented in the Diagnostic and Statistical Manual of Mental Disorders. 

Note: While an informal interview is not recommended as the chief way to diagnose a personality disorder or those within the various personality disorder clusters, it can yield valuable information. This is especially true when you have the opportunity to interview a family member that can provide a long and detailed history.