In DSM-IV-TR, personality disorders are polythetic categories that have defined criteria and for which a certain number must be present to meet the diagnostic threshold. They are defined within a categorical, hierarchical taxonomic system, clustering into three groupings that are based on severity. The categorical approach is practical insofar as it is relatively easy to use for purposes of communication and conceptualization. Much information can be conveyed using a single diagnostic label regarding features, associated conditions, and possible treatment options.

Unfortunately, there are a number of serious problems with the categorical system of personality disorder diagnosis presented in DSM-IV-TR. Personality disorder categories are quite heterogeneous with regard to symptoms and traits (e.g., there are 256 combinations of symptoms that can result in the diagnosis of borderline personality disorder), comorbidity among personality disorder diagnoses is common, and diagnoses do not appear to be very stable over time. Hence, the idea that personality disorders represent distinct diagnostic entities may not be valid and their categorical classification may not be optimal.

An alternative to representing personality pathology and disorder categorically is a dimensional model of classification. Dimensional models provide more reliable scores (e.g., across raters and across time); help to explain symptom heterogeneity and the lack of clear boundaries between categorical diagnoses through the lens of underlying personality traits or dimensions; retain important information about sub-threshold traits and symptoms that may be of clinical interest; and allow for integration of scientific findings concerning the distribution of personality traits and associated maladaptivity into a classification system.

It is possible that a dimensional model of personality disorders will be adopted in future editions of DSM. However, much work will need to be done before the dimensional model is accepted by researchers who study these disorders and clinicians who treat them. Barriers that must be overcome include the perception that dimensional models are more cumbersome and less user-friendly than the cleanly delineated categorical ones. A second concern is determining how appropriate cutoffs would be established for distress or maladaptation and impairment, such that pathology can be established and treated. A final practical issue that must be addressed is that of insurance coverage: third-party payers are not likely to reimburse for treatment unless they know concretely what they are funding and how interventions are tied to diagnosis.

Information is limited about the incidence and prevalence of personality disorders because people with them often do not seek help from professionals. Estimates of their prevalence within clinical settings are typically above 50%. As many as 60% of inpatients within some clinical settings would be diagnosed with borderline personality disorder (BPD), and as many as 50% of inmates within a correctional setting could be diagnosed with antisocial personality disorder (ASPD). Although the comorbid presence of a personality disorder is likely to have an important impact on the course and treatment of an Axis I disorder, the prevalence of personality disorder is generally underestimated in clinical practice, due in part to the failure to provide systematic or comprehensive assessments of personality disorder symptomatology and perhaps as well to the lack of funding for the treatment of personality disorders.

Approximately 10–15% of the general population would be diagnosed with one of the DSM-IV-TR personality disorders.

The requirement that a personality disorder be evident since late adolescence and be relatively chronic thereafter has been a traditional means with which to distinguish a personality disorder from an Axis I disorder. Mood, anxiety, psychotic, sexual, and other mental disorders have traditionally been conceptualized as conditions that arise at some point during a person’s life and that are relatively limited or circumscribed in their expression and duration. Personality disorders, in contrast, are conditions that are evident as early as late adolescence (and in some instances prior to that time), are evident in everyday functioning, and are stable throughout adulthood.

Little information is available or verifiable about what actually causes personality disorders despite several theories regarding personality development. Some scholars suggest that they actually represent variants of normal personality structure rather than disease processes. Most likely, the DSM-IV-TR personality disorders might be, for the most part, constellations of maladaptive personality traits that are the result of multiple genetic dispositions interacting with a variety of detrimental environmental experiences.

DSM-IV-TR includes ten individual personality disorder diagnoses that are organized into three clusters: (A) paranoid, schizoid, and schizotypal (placed within an odd–eccentric cluster); (B) antisocial, borderline, histrionic, and narcissistic (dramatic–emotional–erratic cluster); and (C) avoidant, dependent, and obsessive–compulsive (anxious– fearful cluster). Two others are included in the appendix to DSM-IV-TR for disorders needing further study (passive–aggressive and depressive). Readers of this text are referred to DSM-IV-TR for specific diagnostic criteria for each.

19.6.1 Cluster A Disorders

People with a Cluster A personality disorder manifest signs and symptoms sometimes associated with the schizophrenic spectrum. In addition to appearing odd or eccentric, those affected often seem cold, withdrawn, suspicious, and irrational.

19.6.1.1 Paranoid Personality Disorder

People with paranoid personality disorder (PPD) are suspicious, quick to take offense, and usually cannot acknowledge their own negative feelings toward others. However, they often project these negative feelings onto others. They have few friends and may project hidden meaning into innocent remarks. They may be litigious and guarded, and they may bear grudges for imagined insults or slights. Marital or sexual difficulties are common and often involve issues related to fidelity. People with PPD are quick to react with anger and counterattack in response to imagined character or reputation attacks. Despite their tendency to interpret the actions of others as deliberately threatening or demeaning, these people do not lose contact with reality.

As children, these individuals may appear odd and peculiar to their peers and they may not have achieved to their capacity in school. Their adjustment as adults will be particularly poor with respect to interpersonal relationships. They may become socially isolated or fanatic members of groups that encourage or at least accept their paranoid ideation. They might maintain a steady employment but will be difficult coworkers, as they will tend to be rigid, controlling, critical, blaming, and prejudicial. They are likely to become involved in lengthy, acrimonious, and litigious disputes that are difficult, if not impossible, to resolve.

There are no systematic studies on the treatment of PPD. Individuals rarely seek treatment for their feelings of suspiciousness and distrust. They will experience these traits as simply accurate perceptions of a malevolent and dangerous world (i.e., ego-syntonic). They may not consider the paranoid attributions to be at all problematic, disruptive, or maladaptive. They will not be delusional, but they will fail to be reflective, insightful, or self-critical. They may recognize only that they have difficulty controlling their anger and getting along with others. They might be in treatment for an anxiety, mood, or substance-related disorder or for various marital, familial, occupational, or social (or legal) conflicts that are secondary to their personality disorder; but they will also externalize the responsibility for their problems and will have substantial difficulty recognizing their own contribution to their internal dysphoria and external conflicts. They will consider their problems to be due to what others are doing to them, not to how they perceive, react, or relate to others.

These individuals are exceedingly difficult to engage in treatment. They are not good candidates for individual or group therapy. People with PPD may perceive the use of a medication to represent an effort to simply suppress or control their accusations and suspicions. However, they may be receptive and responsive to the benefits of a medication to help control feelings of anxiousness or depression that are secondary to their personality disorder.

19.6.1.2 Schizoid Personality Disorder

Schizoid personality disorder (SZPD) is a pervasive pattern of social detachment and restricted emotional expression. Individuals are lifelong loners. They exhibit indifference to social relationships, a flattened affectivity, and a cold, unsociable, reclusive demeanor. They take pleasure in few, if any, activities. People with this disorder usually never marry, have little interest in exploring their sexuality, and frequently live as adult children with their parents or other first-degree relatives.

There are few systematic studies on the childhood antecedents of and adult course of SZPD. Individuals are likely to have been socially isolated and withdrawn as children. They may not have been accepted well by their peers and may have even been the brunt of some peer ostracism. Psychosocial models for the etiology of SZPD are lacking. It is possible that a sustained history of isolation during infancy and childhood, with an encouragement and modeling by parental figures of interpersonal withdrawal, indifference, and detachment, could contribute to the development of schizoid personality traits.

Prototypic cases of SZPD would rarely present for treatment, whether it is for their schizoid traits or a concomitant Axis I disorder. They would feel little need for treatment, as their isolation will often be ego-syntonic. Their social isolation will be of more concern to their relatives, colleagues, or friends than to themselves. Their disinterest in, and withdrawal from, intimate or intense interpersonal contact will also be a substantial barrier to treatment. They will at times appear depressed but one must be careful not to confuse their anhedonic detachment, withdrawal, and flat affect with symptoms of depression.

If a person with SZPD is seen for treatment for a concomitant Axis I disorder (e.g., a sexual arousal disorder or substance dependence), it is advisable to work within the confines and limitations of the schizoid personality traits. Charismatic, engaging, emotional, or intimate therapists can be very uncomfortable, foreign, and even threatening to people with SZPD. A more businesslike approach can be more successful. Patients are perhaps best treated with a supportive psychotherapy that emphasizes education and feedback concerning interpersonal skills and communication.

19.6.1.3 Schizotypal Personality Disorder

People with schizotypal personality disorder (STPD) display an enduring and pervasive pattern of social and interpersonal deficits marked by extreme discomfort with, and intolerance for, close relationships. The symptomatology of STPD has been differentiated into components of positive symptoms (cognitive–perceptual aberrations) and negative symptoms (social aversion and withdrawal) comparable to the distinctions made for schizophrenia.

These individuals may have disturbed thought patterns and manifest odd behavior, speech, and appearance. They may be suspicious and display ideas of reference without delusions of reference. They may be superstitious and believe that they are capable of unusual forms of communication such as telepathy and clairvoyance. Patients with STP have a constricted or otherwise inappropriate affect and lack friends or confidantes other than first-degree relatives. They experience great social anxiety that does not diminish with familiarity and that seems to be associated with paranoid fearfulness rather than issues of low self-esteem.

There is insufficient research to describe the childhood precursors of adult STPD. Persons with STPD would be expected to appear peculiar and odd to their peers during adolescence, and may have been teased or ostracized. Achievement in school might be impaired, and they may have been heavily involved in esoteric fantasies and peculiar interests. As adults, they may drift toward esoteric fringe groups that support their magical thinking and aberrant beliefs. These activities can provide structure for some people with STPD, but they can also contribute to a further loosening and deterioration if there is an encouragement of aberrant experiences.

The symptomatology of STPD does not appear to remit with age. The course appears to be relatively stable, with some proportion of schizotypal persons remaining marginally employed, withdrawn, and transient throughout their lives. There is compelling empirical support for a genetic association of STPD with schizophrenia. Some patients meeting DSM-IV-TR criteria for STPD do eventually go on to develop schizophrenia but the vast majority do not.

Individuals with STPD may seek treatment for their feelings of anxiousness, perceptual disturbances, or depression. Treatment should be cognitive, behavioral, supportive, and/or pharmacologic, as they will often find the intimacy and emotionality of reflective, exploratory psychotherapy to be too stressful and they have the potential for psychotic decompensation.

Most of the systematic empirical research on the treatment of STPD has been confined to pharmacologic interventions. Low doses of antipsychotic medications have shown some effectiveness in the treatment of schizotypal symptoms, particularly the perceptual aberrations and social anxiousness. Group therapy has also been recommended for persons with STPD but only when the group is highly structured and supportive.

19.6.2 Cluster B Disorders

A patient with a Cluster B disorder displays dramatic, emotional, and attention-seeking behaviors. He or she might also display labile and shallow moods and tend to become involved in all kinds of intense interpersonal conflicts.

19.6.2.1 Antisocial Personality Disorder

People with antisocial personality disorder (ASPD) display aggressive, irresponsible behavior that often leads to conflicts with society and involvement in the criminal justice system. People with this disorder commonly display behaviors such as fighting, lying, stealing, abusing children and spouses, abusing substances, and participating in confidence schemes. These people, while often superficially charming, lack genuine warmth.

While the diagnosis of antisocial personality disorder is limited to patients older than 18 years, the person also must have had a history of conduct disorder before 17 years of age.

ASPD will at times be difficult to differentiate from a substance-dependence disorder in young adults because many individuals with ASPD develop a substance-related disorder and many with a substance dependence engage in antisocial acts.