Most of today’s clinicians believe that personality disorders represent important and troubling patterns. Yet, as you read at the beginning of this chapter, DSM-5’s personality disorders are particularly hard to diagnose and easy to misdiagnose, difficulties that indicate serious problems with the validity and reliability of these categories. Consider, in particular, the following problems:

In light of these problems, the leading criticism of DSM-5’s approach to personality disorders is, as you read earlier, that the classification system defines such disorders by using categories—rather than dimensions—of personality. A growing number of theorists believe that personality disorders differ more in degree than in type of dysfunction. Therefore, they propose that the disorders should be classified by the severity of key personality traits (or dimensions) rather than by the presence or absence of specific traits (Morey et al., 2014). In such an approach, each key trait (for example, disagreeableness, dishonesty, or self-absorption) would be seen as varying along a continuum in which there is no clear boundary between normal and abnormal. People with a personality disorder would be those who display extreme degrees of several of these key traits—degrees not commonly found in the general population (see InfoCentral below).

Which key personality dimensions should clinicians use to help identify people with personality problems? Some theorists believe that they should rely on the dimensions identified in the “Big Five” theory of personality, dimensions that have received enormous attention by personality psychologists over the years.

A large body of research consistently suggests that the basic structure of personality may consist of five “supertraits,” or factors—neuroticism, extroversion, openness to experiences, agreeableness, and conscientiousness (Curtis et al., 2014; Zuckerman, 2011). Each of these factors, which are frequently referred to as the “Big Five,” consists of a number of subfactors. Anxiety and hostility, for example, are subfactors of the neuroticism factor, while optimism and friendliness are subfactors of the extroversion factor. Theoretically, everyone’s personality can be summarized by a combination of these supertraits. One person may display high levels of neuroticism and agreeableness, medium extroversion, and low conscientiousness and openness to experiences. In contrast, another person may display high levels of agreeableness and conscientiousness, medium neuroticism and extroversion, and low openness to experiences. And so on.

Many proponents of the Big Five model have argued further that it would be best to describe all people with personality disorders as being high, low, or in between on the five supertraits and to drop the use of personality disorder categories altogether (Glover et al., 2012; Lawton et al., 2011). Thus a particular person who currently qualifies for a diagnosis of avoidant personality disorder might instead be described as displaying a high degree of neuroticism, medium degrees of agreeableness and conscientiousness, and very low degrees of extroversion and openness to new experiences. Similarly, a person currently diagnosed with narcissistic personality disorder might be described in the Big Five approach as displaying very high degrees of neuroticism and extroversion, medium degrees of conscientiousness and openness to new experiences, and a very low degree of agreeableness.

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The “Big Five” approach to personality disorders is currently receiving study and may wind up being used in the next edition of the World Health Organization’s International Classification of Diseases (ICD), the classification system for medical and psychiatric diagnoses used in many countries outside the United States (Aldhous, 2012). In the meantime, as you read earlier, the DSM-5 framers have designed their own alternative dimensional approach for possible use in a future revision of the DSM.

This approach begins with the notion that people whose traits significantly impair their functioning should receive a diagnosis called personality disorder—trait specified (PDTS) (APA, 2013). When assigning this diagnosis, clinicians would also identify and list the problematic traits and rate the severity of impairment caused by them. According to the proposal, five groups of problematic traits would be eligible for a diagnosis of PDTS: negative affectivity, detachment, antagonism, disinhibition, and psychoticism.

If a person is impaired significantly by any of the five trait groups, or even by just 1 of the 25 traits that make up those groups, he or she would qualify for a diagnosis of personality disorder—trait specified. In such cases, the diagnostician would indicate which traits are impaired.

Consider, for example, Matthew, the unhappy 34-year-old accountant described on page 450. As you’ll recall, Matthew meets the criteria for a diagnosis of dependent personality disorder under DSM-5’s current categorical approach, based largely on his lifetime of extreme dependence on his mother, friends, and coworkers. Using the alternative dimensional approach suggested in DSM-5, a diagnostician would instead observe that Matthew is significantly impaired by several of the traits that characterize the negative affectivity trait group. He is, for example, greatly impaired by “separation insecurity.” This trait has prevented him from completing college, living on his own, marrying his girlfriend, ever disagreeing with his mother, advancing at work, and broadening his social life. In addition, Matthew seems to be impaired significantly by the traits of “anxiousness,” “submissiveness,” and “depressivity.” Given this picture, his therapist might assign him a diagnosis of personality disorder—trait specified, with problematic traits of separation insecurity, anxiousness, submissiveness, and depressivity.

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According to this dimensional approach, when clinicians assign a diagnosis of personality disorder—trait specified, they also must rate the degree of dysfunctioning caused by each of the person’s traits, using a five-point scale ranging from “little or no impairment” (Rating = 0) to “extreme impairment” (Rating = 4).

Consider Matthew once again. He would probably warrant a rating of “0” on most of the 25 traits listed in the DSM-5 proposal, a rating of “3” on the trait of anxiousness and depressivity, and a rating of “4” on the traits of separation insecurity and submissiveness. Altogether, he would receive the following cumbersome, but informative, diagnosis:

Diagnosis: Personality Disorder—Trait Specified

Separation insecurity: Rating 4

Submissiveness: Rating 4

Anxiousness: Rating 3

Depressivity: Rating 3

Other traits: Rating 0

This dimensional approach to personality disorders may indeed prove superior to DSM-5’s current categorical approach. Thus far, however, it has caused its own stir in the clinical community. Many clinicians believe that the proposed changes would give too much latitude to diagnosticians—allowing them to apply diagnoses of personality disorder to an enormous range of personality patterns. Still others worry that the requirements of the newly proposed system are too cumbersome or complicated. Only time and research will determine whether the alternative system is indeed a useful approach to the diagnosis of personality disorders.