We have previously reviewed the four defining features of personality disorders. These are:
1) Distorted thinking patterns,
2) Problematic emotional responses,
3) Over- or under-regulated impulse control, and
4) Interpersonal difficulties.
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 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 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.
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: Paranoid, Schizoid, and Schizotypal Personality Disorders
Cluster A is called the odd, eccentric cluster. It includes Paranoid Personality Disorder, Schizoid Personality Disorder, and Schizotypal Personality Disorders. The common features of the personality disorders in this cluster are social awkwardness and social withdrawal. These disorders are dominated by distorted thinking.
The Paranoid Personality Disorder* is characterized by a pervasive distrust and suspiciousness of other people. People with this disorder assume that others are out to harm them, take advantage of them, or humiliate them in some way. They put a lot of effort into protecting themselves and keeping their distance from others. They are known to preemptively attack others whom they feel threatened by. They tend to hold grudges, are litigious, and display pathological jealously. Distorted thinking is evident. Their perception of the environment includes reading malevolent intentions into genuinely harmless, innocuous comments or behavior, and dwelling on past slights. For these reasons, they do not confide in others and do not allow themselves to develop close relationships. Their emotional life tends to be dominated by distrust and hostility.
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 don't seem to seek out or enjoy close relationships. They almost always chose solitary activities, and seem to take little pleasure in life. These "loners" often prefer mechanical or abstract activities that involve little human interaction and appear indifferent to both criticism and praise. Emotionally, they seem aloof, detached, and cold. They may be oblivious to social nuance and social cues causing them to appear socially inept and superficial. 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 Schizoid Personality Disorder appears to be rather rare.
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. People with Schizotypal Personality Disorder have odd beliefs, for instance, they may believe they can read other people's thoughts, or that that their own thoughts have been stolen from their heads. These odd or superstitious beliefs and fantasies are inconsistent with cultural norms. 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 (Coccaro & Siever, 2005).
*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.