Abnormal Psychology

Dissociative and Somatoform Disorders 341

Neurological Factors

As we’ll see in the following sections, studies have

addressed changes in brain systems and neural communi-

cation in people who have this disorder.

Brain Systems One PET study of patients with deper-

sonalization disorder found unusual levels of activation

(either too high or too low) in parts of the brain specifi cally

involved in various phases of perception (Simeon et al.,

2000). More specifi cally, the study found lower than nor-

mal activity in parts of the temporal lobe that are involved

in visual and auditory recognition and higher than normal

activity in parts of the parietal lobe, which is involved in

orienting a person in space and representing the body. The

researchers noted that these fi ndings are consistent with

the idea that depersonalization disorder involves dissocia-

tions in perception.

Researchers have investigated whether depersonaliza-

tion disorder also involves abnormal emotional responses

(Phillips & Sierra, 2003). Specifically, in one study,

researchers scanned the brains of patients with this disor-

der and the brains of matched controls while participants

viewed pictures of neutral or aversive scenes. The research-

ers found that the aversive stimuli produced less activation

in brain regions involved in emotional reactions (specifi -

cally, disgust) in the patients than in the controls. However,

the aversive pictures had the opposite effect on part of the

right frontal lobe in the patients, causing it to be unusually

activated; this area is involved in regulating emotion. The

fi ndings may suggest that patients with depersonalization disorder regulate their

emotions more strongly than normal—which may be why they have weaker than

normal emotional reactions (Phillips et al., 2001).

Other studies converge in providing evidence that

depersonalization disorder arises, at least in part, from dis-

ruptions of emotional processing (Sierra et al., 2002). For

example, when patients with this disorder viewed faces

with highly emotional expressions, activity in the limbic

system decreased—and this occurred in response to both

very happy and very sad expressions (Lemche et al., 2007).

This study also showed that the patients had unusually

high levels of activity in the frontal lobes when viewing

such facial expressions. This is important, because if the

frontal lobes can suppress emotional responses, the result

might be the sense of emotional detachment that such

patients report. Such an effect might also explain why

brain areas involved in emotion are not activated when

patients with depersonalization disorder try to remember

words that name emotions, whereas these brain areas are

activated when normal control participants perform this

task (Medford et al., 2006).

Neural Communication Patients with depersonalization disorder do not produce nor-

mal amounts of norepinephrine. In fact, the more strongly they exhibit symptoms of

the disorder, the less norepinephrine they apparently produce (as measured in their

urine; Simeon, Guralnick, et al., 2003). Norepinepherine is associated with activity

of the autonomic nervous system, and thus this fi nding is consistent with the idea

that these patients have blunted responses to emotion.

Table 8.6 • Depersonalization Disorder Facts at a Glance

Prevalence

• The prevalence of depersonalization disorder is unknown, but thought to
  be extremely low.

Comorbidity

• People with depersonalization disorder may also have symptoms of anxiety
  (Bremner et al., 1998; Marshall et al., 2000; Segui et al., 2000). In one sam-
  ple of 204 people with depersonalization disorder, almost three quarters
  had had an anxiety disorder (Baker et al., 2003).


• Other comorbid symptoms include depression, bodily concerns, and obses-
  sive rumination.

Onset

• The average age of onset of depersonalization disorder is 16 years old.


• Episodes of depersonalization can be triggered by a wide range of events,
  including trauma, extreme stress, depression, panic, and the ingestion of
  a psycho active drug such as marijuana or alcohol (Raimo et al., 1999; Sim-
  eon, Knutelska, et al., 2003).

Course

• Episodes of depersonalization can last from seconds to years.

Gender Differences

• Twice as many women as men are diagnosed with this disorder.
  Source: Unless otherwise noted, the source is American Psychiatric Association, 2000.

PET scans of the brain of a

healthy person (left) and of

the brain of a patient with

Depersonalization Disorder

(right). Note the increased

activity in the parietal lobes

of the patient; this part of the

brain is involved in orienting

a person in space and in rep-

resenting the body.

Daphne Simeon, M.D, et al., American Journal of Psychiatry 157:1782–1788, November 2000. © 2000 American Psychiatric Association