What are Cluster A Personality Disorders?
Cluster A personality disorders encompass a group of mental health conditions characterized by peculiar, eccentric, or odd behavior. These disorders include Paranoid, Schizoid, and Schizotypal personality disorders, sharing features like social withdrawal, distorted thinking patterns, and issues in forming and maintaining relationships. These disorders can only be diagnosed by a mental health professional, such as a psychological or therapist. >>>
Intro to Personality Disorders
We have previously reviewed the four defining features of personality disorders. These are:
1) Distorted perception and thinking patterns,
2) Problematic emotional responses,
3) Over- or under-regulated impulse control, and
4) Interpersonal difficulties.
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These four core features are common to all personality disorders. Before a diagnosis is made, a person must demonstrate significant and enduring difficulties in at least two of those four areas. Furthermore, personality disorders are not usually diagnosed in children because of the requirement that personality disorders represent enduring problems across time.
These four key features combine in various ways to form ten specific personality disorders identified in DSM-5 (APA, 2013). Each disorder lists asset of criteria reflecting observable characteristics associated with that disorder.
In order to be diagnosed with a mental health condition or specific personality disorder, a person must meet the minimum number of criteria established for that disorder. Furthermore, to meet the diagnostic requirements for a psychiatric disorder, the symptoms must cause functional impairment and/or subjective feelings of distress. This means the symptoms are distressing to the person with the disorder and/or the symptoms make it difficult for them to function well in society.
The Three Personality Disorder Clusters
Furthermore, the ten different personality disorders can be grouped into three clusters based on descriptive similarities within each cluster. These clusters are:
Cluster A (the "odd, eccentric" cluster);
Cluster B (the "dramatic, emotional, erratic" cluster); and,
Cluster C (the "anxious, fearful" cluster).
Oftentimes, a person can be diagnosed with more than just one personality disorder. Research has shown that there is a tendency for personality disorders within the same cluster to co-occur (Skodol, 2005). Later, this issue of co-occurrence will be discussed in greater detail. The alternative model of personality disorder, proposed for further study in DSM-5 (APA, 2013), hopes to reduce this overlap by using a dimensional approach versus the present categorical one. These different models are discussed in another section.
Now let's look at how all four core features merge to create specific patterns called personality disorders.
Cluster A Personality Disorders
Cluster A Personality Disorders Include: Paranoid, Schizoid, and Schizotypal Personality Disorders.
What is Cluster A Personality Disorder?
Cluster A Personality Disorder is a condition characterized by odd, eccentric, and unusual behaviors or beliefs. People with this personality disorder may have trouble forming close relationships and may have odd or cold traits that can lead to criticism from others. Some common symptoms include fear or anxious feelings, unusual beliefs or eccentric ways of thinking, and difficulty confiding in others. Diagnosis of this personality disorder is based on these symptoms, and treatment options may include therapy and medication. If you suspect that you or someone you know may have Cluster A Personality Disorder or a different mental health condition, it's important to seek help from a mental health professional.
Cluster A Personality Disorders are called the odd, eccentric cluster. It includes Paranoid Personality Disorder, Schizoid Personality Disorder, and Schizotypal Personality Disorders. The common features of Cluster A Personality Disorders are social awkwardness and social isolation or withdrawal. These disorders are dominated by distorted thinking.
Paranoid Personality Disorder
The Paranoid Personality Disorder* is characterized by a pervasive distrust and suspiciousness of other people, interpreting their motives as malicious. People with this disorder assume that others are out to harm them, take advantage of them, or humiliate them in some way. As such, they put a lot of effort into protecting themselves and keeping their distance from others. Often, people with Paranoid Personality Disorder display pathological jealousy and are unable or unwilling to form close relationships.
The diagnostic criteria for this condition includes: 
- Their emotional life tends to be dominated by distrust and hostility.
- Suspects, without evidence, that others are deceiving, harming, or exploiting them
- Is preoccupied with unjustified doubts about trustworthiness of loved ones
- Is reluctant to divulge information to others because of unwarranted fear the information will be to harm them
- Interprets benign behaviors or comments as threatening
- Consistently holds grudges
- Perceives attacks on their reputation or character that are unfounded, and is quick to react furiously
- Has persistent suspicions, without basis, related to fidelity of romantic partner
Schizoid Personality Disorder
The Schizoid Personality Disorder* is characterized by a pervasive pattern of social detachment and a restricted range of emotional expression. For these reasons, people with this disorder tend to be socially isolated. They may be oblivious to social nuance and social cues causing them to appear socially inept and superficial. These "loners" often prefer mechanical or abstract activities that involve little human interaction. Their restricted emotional range and failure to reciprocate gestures or facial expressions (such a smiles or nods of agreement) cause them to appear rather dull, bland, or inattentive.
The diagnostic criteria for Schizoid Personality Disorder includes: 
- Doesn’t want or enjoy close relationships, including being in a family
- Chooses solitary activities the majority of the time
- Has little to no interest in having sexual experiences with others
- Finds pleasure in few, if any, activities
- Lacks confidants or close friends besides first-degree relatives
- Appears indifferent to the criticism or praise of others
- Displays flattened affect, detachment, or emotional coldness
The Schizoid Personality Disorder appears to be rather rare. The prevalence is estimated to be between 3% and 5% in clinical settings.
Schizotypal Personality Disorder
Persons with Schizotypal Personality Disorder* are characterized by a pervasive pattern of social and interpersonal limitations. They experience acute discomfort in social settings and have a reduced capacity for close relationships. For these reasons they tend to be socially isolated, reserved, and distant. Unlike the Schizoid Personality Disorder, they also experience perceptual and cognitive distortions and/or eccentric behavior. These perceptual abnormalities may include noticing flashes of light no one else can see, or seeing objects or shadows in the corner of their eyes and then realizing that nothing is there.
The diagnostic criteria for Schizotypal Personality Disorder includes:
- Ideas of reference, interpreting random events as being meaningful to them
- Strange beliefs or magical thinking that influences behavior (e.g. superstitiousness and belief in telepathy)
- Unusual perceptual experiences, suc has bodily illusions (like thinking they are levitating)
- Bizarre speech and thinking patterns
- Paranoid ideation or intense suspiciousness
- Constricted or inappropriate affect
- Peculiar or eccentric appearance or behavior
- Lack of confidants or close relationships
- Profound social anxiety that is often associated with paranoid fears
Schizotypal Personality Disorder tends to be found more frequently in families where someone has been diagnosed with Schizophrenia; a severe mental disorder with the defining feature of psychosis (the loss of reality testing). There is some indication that these two distinct disorders share genetic commonalities. 
Between 30% and 50% of people diagnosed with this personality disorder have co-occurring major depressive disorder when admitted to treatment. This condition is relatively rare, with prevalence in the community ranging from .6% to 4.6%.
Read about Cluster B Personality Disorders: Borderline Personality Disorder, Narcissistic Personality Disorder, Histrionic Personality Disorder, and Antisocial Personality Disorder.
*It is important to remember that everyone can exhibit some of these personality traits from time to time. To meet the diagnostic requirement of a personality disorder, these traits must be inflexible; i.e., they can be repeatedly observed without regard to time, place, or circumstance. Furthermore, these traits must cause functional impairment and/or subjective distress. The above list only briefly summarizes these individual Cluster A personality disorders. Richer, more detailed descriptions of these disorders are found in the section describing the four core features of personality disorders.
What Cluster is Schizophrenia?
Schizophrenia is not classified under any personality disorder cluster. It is a severe mental illness characterized by a range of symptoms such as delusions, hallucinations, disorganized speech and behavior, and diminished emotional expression. Unlike personality disorders, schizophrenia is not characterized by a specific set of traits or behaviors, but rather by a collection of symptoms that affect a person's thoughts, emotions, and behaviors. The exact cause of schizophrenia is not known, but it is believed to be a combination of genetic and environmental factors. Treatment for schizophrenia typically involves a combination of antipsychotic medication and psychotherapy.
How Many Clusters of Personality Disorders Are There?
There are three clusters of personality disorders as defined by the Diagnostic and Statistical Manual of Mental Disorders (DSM-5).
Cluster A disorders are characterized by odd or eccentric behaviors and thoughts, including paranoid, schizoid, and schizotypal personality disorders.
Cluster B disorders are characterized by dramatic, emotional, or erratic behaviors and include borderline personality disorder, narcissistic personality disorder, histrionic personality disorder, and antisocial personality disorders.
Cluster C disorders are characterized by anxious or fearful behaviors and include avoidant, dependent, and obsessive-compulsive personality disorders.
Each cluster has its own set of symptoms and requires different approaches to treatment. It is important to seek professional attention if you or someone you know is experiencing distress or difficulty managing their behaviors or emotions.
Diagnosing Cluster A Personality Disorders
Diagnosing personality disorders is often more difficult than other mental health conditions like mood disorders, such as depression, anxiety, and bipolar disorder. If you think you or someone you love has a personality disorder, a psychologist who specialized in personality disorders can conduct an evaluation.
To properly diagnose a Cluster A personality disorder, a mental health professional will do the following:
- Conduct a clinical assessment, including interviews and structured evaluations to gather information about behaviors, emotions, and thoughts.
- Observe the patient’s behavior to assess relationships and social functioning.
- Administer personality tests, such as the Minnesota Multiphasic Personality Inventory (MMPI).
- Gather information from other people close to the patient, such as family members.
- Refer to the DSM-5 criteria to determine if the observed patterns align with the specific Cluster A personality disorder.
- Consider cultural factors that may influence behaviors, feelings, and thoughts, ensuring a culturally sensitive and accurate diagnosis.
- Collaborate with other mental health professionals like psychiatrists to ensure a comprehensive evaluation and accurate diagnosis.
- Rule out other conditions by conducting a differential diagnosis.
- Assess the impact of the symptoms on daily functioning to determine the severity of the disorder and subsequent treatment plan.
Do I Have a Personality Disorder?
If you or a friend expresses concern about having a personality disorder or other mental health conditions, it is important to respond with care and encourage them to seek professional help. They may feel anxious or overwhelmed and need support during this time.
It is important to let them know that seeking an assessment from a doctor or mental health professional can provide valuable information and help them understand their thoughts, feelings, and behaviors better. They may find it difficult to read or understand the results of the assessment, and that is okay. What is important is that they get the treatment they need to manage any symptoms or problems in their life.
Take control of your mental health by taking a mental health disorder test.
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- American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). https://doi.org/10.1176/appi.books.9780890425596
- Siever L. J. (2005). Endophenotypes in the personality disorders. Dialogues in clinical neuroscience, 7(2), 139–151. https://doi.org/10.31887/DCNS.2005.7.2/lsiever