All of the disorders we have considered so far are included on Axis I of the DSM. Each involves a specific syndrome with a well-defined set of signs and symptoms. DSM’s Axis II diagnoses, in contrast, are characterized by much broader patterns ofbehaviors and problems that are much more consistent across the lifespan (Clark, 2009). These diagnoses are concerned with traits or habits that characterize almost everything a person does, and so are disorders, in essence, in someone’s personality.
Of course, people differ widely in their personalities , and, because of these variations, some people are easier to be with than others, and some have a smoother path through life than others. In some cases, though, a person’s personality is so maladaptive that it creates considerable distress both for that person and for those around her and impairs the person’s day-to-day functioning. Someone with these dif-ficulties may well be diagnosed as having one or another of the personality disorders.
The DSM recognizes 10 personality disorders. These are paranoid personality disorder (in which a person shows widespread suspiciousness and mistrust of others); schizoidpersonality disorder (in which a person shows a striking detachment from others); schizo-typal personality disorder (in which a person shows a discomfort with close relationships,cognitive or perceptual distortions, and odd behavior); antisocial personality disorder (in which a person shows consistent disregard for—and violation of—others’ rights); borderline personality disorder (in which a person shows impulsive behavior and markedinstability in relationships, self-concept, and affect); histrionic personality disorder (in which a person shows an unusual degree of attention seeking and emotionality); narcissistic personality disorder (in which a person is grandiose, lacks empathy, and needsthe attention and admiration of others); avoidant personality disorder (in which a person shows social inhibition and social insecurity); dependent personality disorder (in which a person shows an excessive need to be taken care of by others); and obsessive-compulsivepersonality disorder (in which a person is preoccupied with orderliness, perfection, andcontrol). Each of these disorders, and indeed all of the Axis II personality disorders, are difficult to diagnose, and disagreements about diagnosis are common (L. A. Clark & Harrison, 2001; Livesley, 2001).
Part of the difficulty is that the definitions of these disorders tell us what a clear-cut and “pure” case of the disorder might look like. In reality, though, an individual’s traits are likely only to approximate this prototype, and many people have traits that leave them resembling more than one of the prototypes (Shea, 1995). This obviously makes diagnosis complicated. In addition, each of these disorders can be thought of as merely the extreme of some ordinary pattern (Livesley, 2001; Widiger & Sanderson, 1995). Many people, for example, are vain, and it is therefore a judgment call whether some-one’s vanity is so powerful that it signals a narcissistic personality disorder. Likewise, many people are shy, and it is sometimes difficult to decide whether someone’s shyness is consistent with avoidant personality disorder. Clinicians often disagree in these judgments, increasing the uncertainty of the Axis II diagnoses.
These diagnostic problems have in turn been difficult for researchers, because it is obviously hard to study a group that cannot be accurately identified (Clark, 2007). Despite this limitation, investigators have made impressive progress in understanding several of the personality disorders. For example, the diagnosis of antisocial personal-ity disorder (and the closely related diagnosis of psychopathy) is a powerful predictor of whether someone will slide into crime again after a period of imprisonment (Hare, Cooke, & Hart, 1999; Hemphill, Hare, & Wong, 1998) and so can be an important source of information in making parole decisions about a prisoner. Similarly, the diag-nosis of borderline personality disorder predicts compromised social cognition, as evi-denced in neuroimaging findings that show that people with borderline personality disorder fail to discriminate between situations in which another person signaled that they trusted the diagnosed individual and situations in which the other person signaled no trust (King-Casas, Sharp, Lomax-Bream, Lohrenz, Fonagy, & Montague, 2008;Meyer-Lindenberg, 2008).