Abnormal Psychology

334 CHAPTER 8

anddissociative identity disorder. People whose symptoms do not fi t neatly into

the criteria of one of these disorders may be diagnosed with dissociative dis-

order not otherwise specifi ed (DDNOS). Someone who has some, but not all,

of the symptoms required for a diagnosis of one of the dissociative disorders,

but whose functioning is nonetheless impaired because of those symptoms, will

be diagnosed with DDNOS. The prevalence rate for DDNOS approaches those

for the other dissociative disorders (Lipsanen et al., 2004), which means that as

many people are diagnosed with DDNOS as are diagnosed with any of the other

dissociative disorders.

The relatively high prevalence of DDNOS compared to the other four dissocia-

tive disorders suggests that the criteria for these four disorders may not adequately

represent the underlying phenomena. That is, the diagnostic criteria for each of the

dissociative disorders may be too narrow or strict, and thus the symptoms of some

patients with signifi cant dissociation don’t “fi t” the criteria neatly.

Dissociative Amnesia

Anna’s native language was German, but as her condition began to worsen while

she was nursing her father, she started to speak only English (a language in which she

was also fl uent). She developed complete amnesia for speaking the German lan-

guage. Let’s examine why her amnesia for speaking in her native language might be

considered dissociative.

What Is Dissociative Amnesia?

Dissociative amnesia is a dissociative disorder in which the sufferer has signifi -

cantly impaired memory for important experiences or personal information that

cannot be explained by ordinary forgetfulness (see Table 8.1). The experiences

or information typically involve traumatic or stressful events, such as occasions

when the patient has been violent or tried to hurt herself or himself; the amnesia

can come on suddenly. For example, soon after a bloody and dangerous battlefi eld

situation, a soldier may not be able to remember what happened. To qualify as

dissociative amnesia, the memory problem cannot be explained better by another

psychological disorder, a medical disorder, or substance use; as with all dissociative

disorders, it must also signifi cantly impair functioning or cause distress (American

Psychiatric Association, 2000). In Anna’s case, her amnesia for speaking German

could not really be considered as the loss of personal information, but conceivably

could be construed as the loss of an important experience and couldn’t be better

explained by another disorder—and her father’s illness and declining health

had been extremely stressful for her. In this case—the forgotten material

(how to speak German) is not directly related to the stressful event—

her father’s declining health. Nonetheless, her memory problems

appear to be best explained as dissociative amnesia.

The memory problems in dissociative amnesia can take any of

several forms:

• Generalized amnesia, in which the individual can’t remember his or
  her entire life. Although common in television shows, this type of amnesia
  is, in fact, extremely rare.


• Selective amnesia, in which the individual can remember some
  of what happened in an otherwise forgotten period of time. For in-
  stance, a soldier may forget about a particularly traumatic battlefi eld
  skirmish, but remember what he and another person spoke about be-
  tween phases of this skirmish.


• Localized amnesia, in which the individual has a memory gap for a
  specifi c period of time, often a period of time just prior to the stress-
  ful event, as occurred with Mrs. Y in Case 8.1.

Additional facts about dissociative amnesia are listed in Table 8.2.

Table 8.1 • DSM-IV-TR Diagnostic Criteria for

Dissociative Amnesia

A. The predominant disturbance is one or more episodes of inabil-

ity to recall important personal information, usually of a traumatic

or stressful nature, that is too extensive to be explained by ordinary

forgetfulness.

B. The disturbance does not occur exclusively during the course of

Dissociative Identity Disorder, Dissociative Fugue [both discussed

later in this chapter], Posttraumatic Stress Disorder, Acute Stress

Disorder [both in Chapter 7], or Somatization Disorder [discussed

later in this chapter] and is not due to the direct physiological

effects of a substance (e.g., a drug of abuse, a medication) or a

neurological or other general medical condition (e.g., Amnestic

Disorder Due to Head Trauma [discussed in Chapter 15]).

C. The symptoms cause clinically signifi cant distress or impairment

in social, occupational, or other important areas of functioning.

Source: R. Mayou and A. Farmer (2002) Functional somatic symptoms and

syndromes. British Medical Journal 325, 265–268, Copyright 2002. For more

information see the Permissions section.

Soldiers with dissociative amnesia may forget

combat experiences that were particularly

troubling or traumatic. This soldier is attending

a memorial service in Iraq for three of his

comrades who were killed in a convoy attack.

JEWEL SAMAD/AFP/Getty Images

Dissociative amnesia

A dissociative disorder in which the

sufferer has signifi cantly impaired memory

for important experiences or personal

information that cannot be explained by

ordinary forgetfulness.