Dissociative Amnesia
Dissociative Amnesia
Definition
Dissociative amnesia is classified by the Diagnostic and Statistical Manual of Mental Disorders, fourth edition, text revision (also known as the DSM-IV-TR), as one of the dissociative disorders, which are mental disorders in which the normally well-integrated functions of memory, identity, perception, or consciousness are separated (dissociated). The dissociative disorders are usually associated with trauma in the recent or distant past, or with an intense internal conflict that forces the mind to separate incompatible or unacceptable knowledge, information, or feelings. In dissociative amnesia, the continuity of the patient’s memory is disrupted. Patients with dissociative amnesia have recurrent episodes in which they forget important personal information or events, usually connected with trauma or severe stress. The information that is lost to the patient’s memory is usually too extensive to be attributed to ordinary absentmindedness or forgetfulness related to aging. Dissociative amnesia was formerly called “psychogenic amnesia.”
Amnesia is a symptom of other medical and mental disorders; however, the patterns of amnesia differ depending on the cause of the disorder. Amnesia associated with head trauma is typically both retrograde (the patient has no memory of events shortly before the head injury) and anterograde (the patient has no memory of events after the injury). The amnesia that is associated with seizure disorders is sudden onset. Amnesia in patients with delirium or dementia occurs in the context of extensive disturbances of the patient’s cognition (knowing), speech, perceptions, emotions, and behaviors. Amnesia associated with substance abuse , which is sometimes called a “blackout,” typically affects only short-term memory and is irreversible. In dissociative amnesia, in contrast to these other conditions, the patient’s memory loss is almost always anterograde, which means that it is limited to the period following the traumatic event (s). In addition, patients with dissociative amnesia do not have problems learning new information.
Dissociative amnesia as a symptom occurs in patients diagnosed with dissociative fugue and dissociative identity disorder. If the patient’s episodes of dissociative amnesia occur only in the context of these disorders, a separate diagnosis of dissociative amnesia is not made.
Description
Patients with dissociative amnesia usually report a gap or series of gaps in their recollection of their life history. The gaps are usually related to episodes of abuse or equally severe trauma, although some persons with dissociative amnesia also lose recall of their own suicide attempts, episodes of self-mutilation, or violent behavior.
Five different patterns of memory loss have been reported in patients with dissociative amnesia:
- localized. The patient cannot recall events that took place within a limited period of time (usually several hours or one to two days) following a traumatic event. For example, some survivors of the World Trade Center attacks do not remember how they got out of the damaged buildings or what streets they took to get away from the area.
- selective. The patient can remember some, but not all, of the events that took place during a limited period of time. For example, a veteran of D-Day (June 6, 1944) may recall some details, such as eating a meal on the run or taking prisoners, but not others (seeing a close friend hit or losing a commanding officer).
- generalized. The person cannot recall anything in his/her entire life. Persons with generalized amnesia are usually found by the police or taken by others to a hospital emergency room.
- continuous. The amnesia covers the entire period without interruption from a traumatic event in the past to the present.
- systematized. The amnesia covers only certain categories of information, such as all memories related to a certain location or to a particular person.
Most patients diagnosed with dissociative amnesia have either localized or selective amnesia. Generalized amnesia is extremely rare. Patients with generalized, continuous, or systematized amnesia are usually eventually diagnosed as having a more complex dissociative disorder, such as dissociative identity disorder.
Causes and symptoms
Causes
The primary cause of dissociative amnesia is stress associated with traumatic experiences that the patient has either survived or witnessed. These may include such major life stressors as serious financial problems, the death of a parent or spouse, extreme internal conflict, and guilt related to serious crimes or turmoil caused by difficulties with another person.
Susceptibility to hypnosis appears to be a predisposing factor in dissociative amnesia. Thus far, no specific genes have been associated with vulnerability to dissociative amnesia.
Some personality types and character traits seem to be risk factors for dissociative disorders. A group of researchers in the United States has found that persons diagnosed with dissociative disorders have much higher scores for immature psychological defenses than normal subjects.
Symptoms
The central symptom of dissociative amnesia is loss of memory for a period or periods of time in the patient’s life. The memory loss may take a variety of different patterns, as described earlier.
Other symptoms that have been reported in patients diagnosed with dissociative amnesia include the following:
- confusion.
- emotional distress related to the amnesia. However, not all patients with dissociative amnesia are distressed. The degree of emotional upset is usually in direct proportion to the importance of what has been forgotten, or the consequences of forgetting.
- mild depression.
Some patients diagnosed with dissociative amnesia have problems or behaviors that include disturbed interpersonal relationships, sexual dysfunction, employment problems, aggressive behaviors, self-mutilation, or suicide attempts.
Demographics
Dissociative amnesia can appear in patients of any age past infancy. Its true prevalence is unknown. In recent years, there has been an intense controversy among therapists regarding the increase in case reports of dissociative amnesia and the accuracy of the memories recovered. Some maintain that the greater awareness of dissociative symptoms and disorders among psychiatrists has led to the identification of cases that were previously misdiagnosed. Other therapists maintain that dissociative disorders are overdiagnosed in people who are extremely vulnerable to suggestion.
It should be noted that psychiatrists in the United States and Canada have significantly different opinions of dissociative disorder diagnoses. On the whole, Canadian psychiatrists, both French- and English-speaking, have serious reservations about the scientific validity and diagnostic status of dissociative amnesia and dissociative identity disorder. Only 30% of Canadian psychiatrists think that these two dissociative disorders should be included in the DSM-IV-TR without reservation; and only 13% think that here is strong scientific support for the validity of these diagnoses.
Diagnosis
The diagnosis of dissociative amnesia is usually a diagnosis of exclusion. The doctor will take a detailed medical history, give the patient a physical examination, and order blood and urine tests, as well as an electroencephalogram (EEG) or head x ray to rule out memory loss resulting from seizure disorders, substance abuse (including abuse of inhalants), head injuries, or medical conditions, such as Alzheimer’s disease or delirium associated with fever.
Some conditions, such as age-related memory impairment (AAMI), may be ruled out on the basis of the patient’s age. Malingering can usually be detected in patients who are faking amnesia because they typically exaggerate and dramatize their symptoms; they have obvious financial, legal, or personal reasons (for example, draft evasion) for pretending loss of memory. In addition, patients with genuine dissociative amnesia usually score high on tests of hypnotizability. The examiner may administer the Hypnotic Induction Profile (HIP) or a similar measure that evaluates whether the patient is easily hypnotized. This enables the examiner to rule out malingering or factitious disorder.
There are several standard diagnostic questionnaires that may be given to evaluate the presence of a dissociative disorder. The Dissociative Experiences Scale (DES) is a frequently administered self-report screener for all forms of dissociation. The Structured Clinical Interview for the DSM-IV-TR Dissociative Disorders (SCID-D) can be used to make the diagnosis of dissociative amnesia distinct from the other dissociative disorders defined by the DSM-IV-TR. The SCID-D is a semi-structured interview, which means that the examiner’s questions are open-ended and allow the patient to describe experiences of amnesia in some detail, as distinct from simple “yes” or “no” answers.
Diagnosis of dissociative amnesia in children before the age of puberty is complicated by the fact that inability to recall the first four to five years of one’s life is a normal feature of human development. As part of the differential diagnosis, a physician who is evaluating a child in this age group will rule out inattention, learning disorders , oppositional behavior, psychosis , and seizure disorders or head trauma. To make an accurate diagnosis, several different people (such as teachers, therapists, social workers , or the child’s primary care physician) may be asked to observe or evaluate the child.
Treatments
Treatment of dissociative amnesia usually requires two distinct periods or phases of psychotherapy.
Psychotherapy
Psychotherapy for dissociative amnesia is supportive in its initial phase. It begins with creating an atmosphere of safety in the treatment room. Very often, patients gradually regain their memories when they feel safe with and supported by the therapist. This rapport does not mean that they necessarily recover their memories during therapy sessions; one study of 90 patients with dissociative amnesia found that most of them had their memories return while they were at home alone or with family or close friends. The patients denied that their memories were derived from a therapist’s suggestions, and a majority of them were able to find independent evidence or corroboration of their childhood abuse.
If the memories do not return spontaneously, hypnosis or sodium amytal (a drug that induces a semi-hypnotic state) may be used to help recover them.
After the patient has recalled enough of the missing past to acquire a stronger sense of self and continuity in their life history, the second phase of psychotherapy commences. During this phase, the patient deals more directly with the traumatic episode (s), and recovery from its aftereffects. Studies of the treatments for dissociative amnesia in combat veterans of World War I (1914-1918) found that recovery and cognitive integration of dissociated traumatic memories within the patient’s overall personality were more effective than treatment methods that focused solely on releasing feelings.
Medications
At present, there are no therapeutic agents that prevent amnestic episodes or that cure dissociative amnesia itself. Patients may, however, be given antidepressants or other appropriate medications for treatment of the depression, anxiety, insomnia , or other symptoms that may accompany dissociative amnesia.
Legal implications
Dissociative amnesia poses a number of complex issues for the legal profession. The disorder has been cited by plaintiffs in cases of recovered memories of abuse leading to lawsuits against the perpetrators of the abuse. Dissociative amnesia has also been cited as a defense in cases of murder of adults as well as in cases of neonatricide (murder of an infant shortly after birth). Part of the problem is the adversarial nature of courtroom procedure in the United States, but it is generally agreed that judges and attorneys need better guidelines regarding dissociative amnesia in defendants and plaintiffs
Prognosis
The prognosis for recovery from dissociative amnesia is generally good. The majority of patients eventually recover the missing parts of their past,
KEY TERMS
Age-associated memory impairment (AAMI) —A condition in which an older person suffers some memory loss and takes longer to learn new information. AAMI is distinguished from dementia because it is not progressive and does not represent a serious decline from the person’s previous level of functioning. Benign senescent forgetfulness is another term for AAMI.
Anterograde amnesia —Amnesia for events that occurred after a physical injury or emotional trauma but before the present moment. The type of amnesia that typically occurs in dissociative amnesia is anterograde.
Defense —An unconscious mental process that protects the conscious mind from unacceptable or painful thoughts, impulses, or desires. Examples of defenses include denial, rationalization, projection, and repression.
Delirium —A disturbance of consciousness marked by confusion, difficulty paying attention, delusions, hallucinations, or restlessness. It can be distinguished from dissociative amnesia by its relatively sudden onset and variation in the severity of the symptoms.
Dementia —A group of symptoms (syndrome) associated with a progressive loss of memory and other intellectual functions that is serious enough to interfere with a person’s ability to perform the tasks of daily life. Dementia impairs memory, alters personality, leads to deterioration in personal grooming, impairs reasoning ability, and causes disorientation.
Depersonalization —A dissociative symptom in which the patient feels that his or her body is unreal, is changing, or is dissolving.
Derealization —A dissociative symptom in which the external environment is perceived as unreal or dreamlike.
Dissociation —A reaction to trauma in which the mind splits off certain aspects of the traumatic event from conscious awareness. Dissociation can affect the patient’s memory, sense of reality, and sense of identity.
Dissociative amnesia —A dissociative disorder characterized by loss of memory for a period or periods of time in the patient’s life. May occur as a result of a traumatic event.
Factitious disorder —A type of mental disturbance in which patients intentionally act physically or mentally ill without obvious benefits. It is distinguished from malingering by the absence of an obvious motive, and from conversion disorder by intentional production of symptoms.
Malingering —Knowingly pretending to be physically or mentally ill to avoid some unpleasant duty or responsibility, or for economic benefit.
Retrograde amnesia —Amnesia for events that occurred before a traumatic injury. Retrograde amnesia is not usually found in patients with dissociative amnesia.
Supportive —An approach to psychotherapy that seeks to encourage the patient or offer emotional support to him or her, as distinct from insight-oriented or educational approaches to treatment.
either by spontaneous re-emergence of the memories or through hypnosis and similar techniques. A minority of patients, however, are never able to reconstruct their past; they develop a chronic form of dissociative amnesia. The prognosis for a specific patient depends on a combination of his or her present life circumstances; the presence of other mental disorders; and the severity of stresses or conflicts associated with the amnesia.
Prevention
Strategies for the prevention of child abuse might lower the incidence of dissociative amnesia in the general population. There are no effective preventive strategies for dissociative amnesia caused by traumatic experiences in adult life in patients without a history of childhood abuse.
See alsoAbuse.
Resources
BOOKS
American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 4th ed., Text rev. Washington, D.C.: American Psychiatric Association, 2000.
Beers, Mark H., MD, and Robert Berkow, MD, eds. “Dissociative Amnesia.” The Merck Manual of Diagnosis and Therapy, Whitehouse Station, NJ: Merck Research Laboratories, 2001.
Ellenberger, Henri. The Discovery of the Unconscious. New York: Basic Books, 1970.
Herman, Judith, MD. Trauma and Recovery. 2nd ed., rev. New York: Basic Books, 1997.
Stout, Martha, PhD. The Myth of Sanity: Tales of Multiple Personality in Everyday Life. New York: Penguin Books, 2001.
PERIODICALS
Bremner, J. Douglas, and others. “Neural Mechanisms in Dissociative Amnesia for Childhood Abuse: Relevance to the Current Controversy Surrounding the ‘False Memory Syndrome.”’ American Journal of Psychiatry 153 (1996): S71–82.
Brown, P., O. Van der Hart, and M. Graafland. “Trauma-Induced Dissociative Amnesia in World War I Combat Soldiers. II. Treatment Dimensions.” Australia and New Zealand Journal of Psychiatry 33 (1999): 392–98.
Carrion, V. G., and H. Steiner. “Trauma and Dissociation in Delinquent Adolescents.” Journal of the American Academy of Child and Adolescent Psychiatry 39 (2000): 353–59.
Chu, J. A., and others. “Memories of Childhood Abuse: Dissociation, Amnesia, and Corroboration.” American Journal of Psychiatry 156 (1999): 749–55.
Durst, R., A. Teitelbaum, and R. Aronzon. “Amnestic State in a Holocaust Survivor Patient: Psychogenic Versus Neurological Basis.” Israeli Journal of Psychiatry and Related Sciences 36 (1999): 47–54.
Lalonde, J. K., and others. “Canadian and American Psychiatrists’ Attitudes Toward Dissociative Disorders Diagnoses.” Canadian Journal of Psychiatry 46 (2001): 407–12.
Miller, P. W., and others. “An Unusual Presentation of Inhalant Abuse with Dissociative Amnesia.” Veterinary and Human Toxicology 44 (2002): 17–19.
Pope, Harrison G., Jr. “Recovered Memories of Childhood Abuse: The Royal College of Psychiatrists Issues Important Precautions.” British Medical Journal 316 (February 14, 1998): 713.
Porter, S., and others. “Memory for Murder. A Psychological Perspective on Dissociative Amnesia in Legal Contexts.” International Journal of Law and Psychiatry 24 (2001): 23–42.
Simeon, D., and others. “Personality Factors Associated with Dissociation: Temperament, Defenses, and Cognitive Schemata.” American Journal of Psychiatry 159 (2002): 489–91.
Spinelli, M. G. “A Systematic Investigation of 16 Cases of Neonaticide.” American Journal of Psychiatry 158 (2001): 811–13.
Zanarini, M. C., and others. “The Dissociative Experiences of Borderline Patients.” Comparative Psychiatry 41 (2000): 223–27.
ORGANIZATIONS
International Society for the Study of Dissociation (ISSD). 8201 Greensboro Drive, Suite 300, McLean, VA 22102. Telephone: (703) 610-9037. <http://www.issd.org>.
International Society for Traumatic Stress Studies (ISTSS). 60 Revere Dr., Suite 500, Northbrook, IL 60062. Telephone: (847) 480-9028. <http://www.istss.org>.
National Institute of Mental Health. 6001 Executive Boulevard, Room 8184, MSC 9663, Bethesda, MD 20892-9663. Telephone: (301) 443-4513. <http://www.nimh.nih.gov>.
National Organization for Rare Disorders (NORD). 55 Kenosia Avenue, P.O. Box 1968, Danbury, CT 06813-1968. Telephone: (203) 744-0100. <http://www.rarediseases.org>.
OTHER
National Alliance on Mental Illness, “Dissociative Disorders.” <http://www.nami.org/Content/ContentGroups/Helpline1/Dissociative_Disorders.htm>.
“Symposium: Science and Politics of Recovered Memories.” Special issue of Ethics and Behavior 8 (1998). The issue is based on a program chaired by Gerald Koocher of Harvard Medical School at the 1998 convention of the American Psychiatric Association.
Rebecca Frey, PhD
Emily Jane Willingham, PhD