Abnormal Psychology

Personality Disorders 603

and the hippocampus (De la Fuente et al., 1997; Juengling et al., 2003; Lieb et al.,

2004; Soloff, Meltzer, et al., 2003).

Dysfunction of the anterior cingulate is particularly interesting because this

structure plays a role in controlling affect: When normal control participants ex-

perience emotional and stressful situations, this area is activated; it is not activated

in patients with borderline personality disorder (Schmahl, Elzinga, et al., 2003;

Schmahl et al., 2004). This abnormality might contribute to the problems that peo-

ple with this disorder have in regulating their emotions.

In contrast to the frontal lobes and the anterior cingulate, the amygdala (which is

involved in the perception and production of strong emotions, notably fear) is more

strongly activated than normal in these patients when they see faces with negative

expressions (Donegan et al., 2003). This fi nding makes sense because the frontal lobes

normally inhibit the amygdala (LeDoux, 1996); thus, if the frontal lobes are not work-

ing properly, they may fail to keep activation of the amygdala within a normal range.

In addition, consistent with fi ndings from neuroimaging studies, numerous stud-

ies have shown that people who have borderline personality disorder have diffi culty

performing tasks that rely on the frontal lobes (LeGris & van Reekum, 2006). For

example, they typically have diffi culty inhibiting responses, such as is required in

the Stroop task, where participants name the color of the ink (e.g., the word “red”

is printed in blue ink) used to print the name of a color and the name confl icts with

the color of the ink—and thus responses based on the name of the color must be

inhibited (Kunert et al., 2003; Sprock et al., 2000). People with this disorder also

have diffi culty focusing attention, organizing visual material, and making decisions,

and their visual and verbal memory is impaired (LeGris & van Reekum, 2006).

Neural Communication Relatively low levels of serotonin are related to impulsivity,

which is characteristic of borderline personality disorder. Thus, it is not surprising

that these patients have been shown to have abnormal serotonin functioning (Soloff

et al., 2000); in particular, their serotonin receptors apparently are not as sensitive

as normal, and thus the effects of serotonin are diminished (Hansenne et al., 2002).

In addition, this dysfunction involving serotonin is apparently greater in women

than in men with the disorder (Leyton et al., 2001; New et al., 2003; Soloff, Kelly

et al., 2003)—and many more women than men receive this diagnosis.

But problems with serotonin alone cannot explain the abnormal brain func-

tioning (Lieb et al., 2004). For instance, Rinne and colleagues (2002) showed that

the hypothalamic-pituitary-adrenal (HPA) axis in at least some of these patients is

unusually responsive, which results in excess amounts of cortisol.

The overall effect of these various brain abnormalities is consistent with

Linehan’s theory. According to this theory, people with borderline personality dis-

order are likely to be neurologically vulnerable to emotional dysregulation. This

vulnerability is usually expressed as a low threshold for emotional responding, with

responses that are often extreme and intense. In addition, the brains of these people

are relatively slow to return to a normal baseline of arousal.

Genetics Genetic studies do not fi nd a specifi c transmission of borderline personality

disorder itself (Torgersen et al., 2000). However, they do reveal a genetic vulner-

ability to components of this disorder, such as impulsivity, emotional volatility, and

anxiety (Adams et al., 2001; Heim & Westen, 2005; Skodol, Siever, et al., 2002).

Psychological Factors: Emotions on a Yo-Yo

The core feature of borderline personality disorder is dysregulation—of emotion,

of sense of self, of cognition, and of behavior (Robins, Ivanoff, & Linehan, 2001).

For instance, people with this disorder feel unsure of themselves, of their goals and

values; the one thing they are often sure of, however, is that they are in some way

“bad” or “defective.” They may have been told repeatedly that they’re “too sensi-

tive.” Their behaviors can be extreme: In one instant, they will fl y into a rage over

some inconsequential thing, but in the next instant, they will break down in tears

and beg for reassurance, as Reiland did. These behaviors may inadvertently be rein-

forced by family members’ attention.

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