A Case of Dissociative Amnesia in an Older Woman

David Woo, MD Series Editor: Melinda S. Lantz, MD

Case Presentation

Mrs. CP is a 64-year-old widowed Filipino woman who came to see a psychiatrist at an outpatient mental health clinic. She had been in treatment intermittently since 1998 for depression and anxiety. Her symptoms included anxious mood, insomnia, hypervigilant behavior, tearfulness, poor concentration, and feelings of palpitations. She reported that over the past year she had been more forgetful and distractible, forgetting where she had placed her keys, pocket cash, and other items. She would forget to get off the bus at a familiar stop and could not remember to purchase needed items at the grocery store. Of greater concern, she had left the stove on several times and had limited recollection of this. Mrs. CP’s behavior included unusual incidents such as leaving rotting bananas in the closet and going back into the shower fully clothed after she had just bathed and dressed herself. Because of these behaviors, her younger son and a close friend moved in with her to assist and monitor her behavior.

The first sign of some unusual behavior began one year prior to Mrs. CP’s current treatment when she described episodes of “sleepwalking” during the day. She reported walking for blocks past a location and past an appointment time, and did not realize that she had done so until something distracted her, such as her cell phone ringing or a taxi honking a horn. She felt that she lost brief periods of time. Mrs. CP also spoke of symptoms occurring at night, such as talking in her sleep, and her waking up to find that all of the windows had been opened, or that the television or air conditioner had been turned on without her awareness. The patient’s son had witnessed the patient flailing about at night and talking in her sleep.

However, the patient’s overall functional performance of her activities of daily living and instrumental activities of daily living were not consistent with someone who had a dementing process or an amotivational or inattentional process. She shopped for her food, cooked, paid her bills, and followed up with her medical appointments. On psychological testing, she did not show poor executive planning, aphasia, personality change, or other signs of early dementia. The patient was very uncomfortable about the increasing dependence on others, and felt helpless and concerned that there would not be an explanation forthcoming about her diagnosis.

Mrs. CP had consulted three neurologists from different hospitals in the past and had been told by one that her problem was “anxiety,” by another that it was “stress and depression,” and by a third that she had early-onset Alzheimer’s disease. The patient’s medical history was significant for hypertension, chronic vertigo, osteoarthritis, osteopenia, and gastroesophageal reflux disease. Medications included hydrochlorothiazide 25 mg daily, meclizine 12.5 mg twice daily, and esomeprazole 40 mg daily. She was diagnosed with seizures as a child but had not taken any anticonvulsant medication for many years. Mrs. CP underwent a noncontrast head computed tomography (CT) scan in April 2006, which revealed bilateral frontal volume loss. A subsequent magnetic resonance imaging (MRI) scan of the brain done in September of that year did not reveal such an abnormality. Due to the uncertain history of seizures, she underwent a three-day electroencephalogram (EEG) study with overnight monitoring, which did not reveal any abnormalities. Laboratory work-up was unremarkable.

During her current treatment, the patient received neuropsychological testing due to concerns regarding her diagnosis, possible cognitive loss, and to assist with treatment planning. Following the evaluation, the findings were found to be consistent with major depressive disorder, mild cognitive disorder versus dementia, and that she had a history of post-traumatic stress disorder.

Mrs. CP was born in the Philippines and had had a turbulent childhood and a severe eating disorder early on. She recalled weighing 80 pounds at one point and thinking that she was overweight. She binged and purged, and used diet pills. She was emotionally labile, “became hysterical” at times, had episodes of getting very upset, and other episodes of staring off into space for minutes, frozen, while eating. She also displayed obsessive thoughts about germs and cleanliness. Mrs. CP had many washing rituals due to fears that she would die if she was not clean enough. As a teenager, Mrs. CP had a “nervous breakdown” due to depression, and her father consulted with a psychiatrist. At that time, she was abusing her mother’s diet pills, engaging in purging and excessive coffee drinking, not sleeping for long periods, and then sleeping for days at a time. While she was in her 20s, she made three attempts to end her life, once by overdosing on 50 pills of 10-mg chlordiazepoxide; another time, she overdosed on over-the-counter sleeping pills; and, in a third attempt on her life, she ingested a powder used for her skin. She described feeling driven by the stress of being in an “inescapable, abusive marriage.” Her husband was often drunk, physically abusive, tortured the children—sometimes with an ax—and used them for “target practice.”

Mrs. CP appeared to want help with her problems but was easily overwhelmed and presented with a diagnostic challenge. The psychiatrist was concerned about how to proceed.


Although there have been a number of studies and case reports of dissociative amnesia over the past century, many suffered from methodological weaknesses, and few explored this disorder in older adults.1 Since then, more systematic studies have supported the classic notion that most patients with dissociative amnesia come from severely stressful psychosocial environments, and experienced feelings of shame, guilt, desperation, and conflict.2 The fourth edition of the Diagnostic and Statistical Manual of Mental Disorders, Text Revision (DSM-IV-TR) defines dissociative amnesiaas an inability to recall important personal information, usually of a traumatic or stressful nature, that is too extensive to be explained by normal forgetfulness.3

The amnestic episode is thought to be an intrapsychic defense, excluding painful memories from conscious awareness, and has been associated with childhood abuse, kidnapping, incest, rape, wartime combat experience (“shell shock”), and other threats of death or physical violence, including being a witness to violence.1-3 Intensity, duration, and age of exposure to the traumatic event seem to be critical factors in the development of dissociative amnesia; generally, the stronger, longer, and earlier the exposure, the worse the amnesia.4 Recurrent dissociative amnestic episodes often occur in individuals suffering from a constellation of other dissociative symptoms (depersonalization, derealization, identity confusion, and identity alteration), including the most severe dissociative disorder, dissociative identity disorder.4 Other dissociative disorders include dissociative fugue, depersonalization disorder, and dissociative disorder not otherwise specified.3,5

The epidemiology of dissociative amnesia has not been adequately examined, but the few studies that have been conducted provide some data. The majority of studies conducted with noncombat–related subjects indicate a relatively equal sex incidence. Although a wide range of ages has been reported, most studies report a peak incidence of 2-3% in the third and fourth decades.4 Many researchers think that dissociative amnesia may be more common than previously reported.4,5 Among older adults who have experienced multiple lifetime traumatic events, the prevalence may be as high as 2%. Many of these patients visit Emergency Rooms and primary care physicians but never receive formal psychiatric treatment.6 

Dissociative amnesia is difficult to assess for because it is not observed directly, except in cases of global amnesia; patients often do not complain about the amnesia itself.1,2 In this case, the patient did complain about the amnesia but also complained about other symptoms that usually cause patients to seek medical attention; she had symptoms of anxiety, depression, confusion, difficulty concentrating, and a history of blank spells or gaps in memory. Even when amnesia is confirmed, clinicians may find it difficult to obtain reliable estimates from patients as to the frequency or extent of their amnestic episodes.1,3

Clinicians should pay particular attention to patients’ verbal responses and nonverbal behaviors because these may exhibit patterns that suggest amnesia. Much of the research on dissociative amnesia was based on the analysis of clinical interviews utilizing Steinberg’s Structured Clinical Interview for DSM-IV Dissociative Disorders-Revised (SCID-D-R).7 For example, administration of Steinberg’s SCID-D-R notes that vagueness and inconsistency of response and difficulty in narration of past events may indicate amnesia.7 Other clues that suggest amnesia include a history of unexplained displacement, possession of unfamiliar objects, disavowal of confirmed actions, and any instance of identity loss.1,2,7

Differential Diagnosis
When evaluating a patient presenting with amnesia, clinicians must determine whether the amnesia is a result of a dissociative disorder, another psychiatric disorder, or from an organic cause. The differential diagnosis needs to include the possibility of dementia, as well as organic diseases and other psychiatric disorders that may be harbingers for more serious illness down the line. A thorough medical work-up should be performed. Comorbid depression and anxiety should be addressed at an early point, given the great morbidity they carry for the geriatric population1-5 (Figure).

dissociative amnesia flow chart

Dissociative amnesia. In dissociative amnesia and in the other dissociative disorders, amnesia is functional, resulting from psychogenic rather than organic factors. Severe amnesia in patients with underlying dissociative disorders is often characterized by their inability to recall their age, name, address, or other essential personal information.1,2 If the memory gaps occur in conjunction with other dissociative symptoms, the clinician should rule out one of the other dissociative disorders.3 SCID-D-R–based research indicates that recurrent memory gaps in conjunction with depersonalization, derealization, identity confusion, and identity alteration characterize the symptomatic profile of patients with dissociative identity disorder.7

Other psychiatric etiologies. In the realm of other psychiatric disorders, amnesia occurs often in patients with moderate-to-severe depression.2 However, amnesia associated with depression is characterized by “I don’t know” rather than near misses or confabulations, and it is less severe than the memory loss of true dementia.2,3

Amnestic experiences are also common to patients with histories of alcohol intoxication, abuse, and dependence.6 Substance abuse patients without coexisting dissociative symptoms (derealization, depersonalization, identity confusion) reported amnesia only in the context of substance use (ie, alcoholic blackouts precipitated by drinking). In these patients, the diagnosis of dissociative amnesia is excluded when substance abuse patients report that their amnesia occurs only in the context of alcohol consumption.6,7

Organic causes. Examples of organic etiologies of amnesia include dementia, epileptic seizures, head trauma, alcoholic blackouts, Korsakoff’s syndrome, stroke, postoperative amnesia, postinfectious amnesia, post-electroconvulsive therapy (ECT), surgery, infection, and transient global amnesia.3-6 Other causes include cerebrovascular disease, metabolic abnormalities, and toxic states. Organic amnesias have several distinguishing features: they do not normally involve recurrent identity alteration; the amnesia is not selectively limited to personal information; the memories do not focus on or result from an emotionally traumatic event; and the amnesia is more often anterograde than retrograde.3 If the patient presents with amnesia and symptoms suggestive of an underlying medical disorder, a complete history of the patient’s behavior during the amnesia should be obtained, as well as a physical and neurological examination including laboratory tests and an EEG.3-5

Amnesia that occurs in the context of an epileptic seizure is called ictal amnesia and is characterized by short duration and epileptiform EEG results.3 In cases of ictal amnesia, there is often anterograde amnesia during the seizure and retrograde amnesia following the seizure. The individual retains a sense of identity and appears otherwise normal. A systematic investigation of amnesia and other dissociative symptoms performed in patients with epilepsy and pseudoseizures (a psychogenic cause of amnesia) found that patients with epilepsy experienced significantly less amnesia, depersonalization, identity confusion, and alteration than patients with pseudoseizures when assessed by SCID-D-R.7 Once an organic cause has been ruled out, the clinician can evaluate the possible causes of psychogenic amnesia. Use of diagnostic tools such as the SCID-D-R can allow assessment of the severity of the amnesia, as well as other core dissociative symptoms, thus enabling the clinician to rule out the presence of a dissociative disorder.2,7

Course and Prognosis
In most cases of dissociative amnesia, individuals experience sudden onset of amnesia, usually following severe psychosocial stressors.1,7 When amnesia is localized or selective, recovery is usually complete, and termination can be rapid. In cases of generalized amnesia, recovery of memory is usually gradual. Functional impairment varies from mild to severe, depending on the extent of the amnesia. When the dissociative amnesia is recurrent, the clinician should rule out the presence of another more severe dissociative disorder, such as dissociative identity disorder.3,4

The more acute and the more recent the instance of dissociative amnesia, the more likely and more quickly it is to be resolved.8 However, the clinician should be prepared to deal with the risk of retraumatization if the attempts to retrieve dissociated memories are too intrusive.1 The risk is greatest for longstanding or childhood-onset amnesias. The clinician should control the pace of suggested recollection, usually within the framework of a broader psychotherapy gauged at resolving more current events producing the amnesia. Once the patient has been stabilized and achieves a sense of safety in the therapeutic relationship, other measures can be initiated. These include group therapy, which has been successful in helping combat veterans and survivors of childhood abuse regain function.1,4 Hypnosis can help contain and modulate symptoms, facilitate recall of dissociated memories, and reintegrate dissociated material. Pharmacotherapy lacks formal double-blind studies to evaluate its efficacy in the treatment of dissociative amnesia, but the development of diagnostic tools such as the SCID-D-R, which assesses for the presence and severity of dissociative symptoms, should allow for systematic research into the treatment of this disorder.7,8 In the case patient, pharmacotherapy provided relief for her anxiety and depression, which provided a sense of control in her treatment, and ultimately led to improvement.

Treating the elderly patient with possible dissociative amnesia can be more complex than doing so in a younger patient.5,8 After a diagnosis of dissociative amnesia is made, the patient will benefit from the development of a consistent and trusting relationship with the clinician. Individual psychotherapy, group therapy, family therapy, medication management, and hypnosis are some of the useful modalities the clinician can utilize.8

Information on dissociative disorders for patients and families may be downloaded from the National Alliance on Mental Illness website at www.nami.org.

Outcome of the Case Patient

Following the neuropsychological testing, Mrs. CP received group therapy for persons with cognitive difficulties, individual weekly supportive psychotherapy, and monthly medication management. She was started on the antidepressant sertraline 50 mg daily, which provided some relief of anxiety. Throughout her treatment sessions with her psychiatrist, the patient often was tearful and described her efforts to repress her sadness. She also reported constant guilt and worry over the two most troubled of her children who live in the Philippines: her oldest son, an alcoholic with seven children, and her daughter, who has a long history of addiction and can barely care for her eight children. The patient resisted taking psychotropic medication for a long time, but she finally relented amidst worries that worsened whenever she got news about her son’s developing alcohol addiction.

The patient was entered into a memory group, where she was given support among others with memory impairments, mostly due to dementia. Although she learned some strategies to improve her memory, she continued to have visceral symptoms of anxiety, such as shallow breathing and palpitations, and increased experiences of memory lapses at those times. Sertraline was titrated up over a month to 100 mg daily for depression and anxiety. Gabapentin was initiated and titrated up to 300 mg at bedtime to help her sleep at night. Both Mrs. CP’s friend and son said that the patient continued to flail around at night and talk in her sleep. However, over the next six months, the patient gradually reported fewer episodes of “losing time” or doing things she could not remember. She reported that the medications helped her to not feel “hysterical” talking about the past; in the past, recalling these events would have triggered intense sadness and tearfulness.

In response to concerns about her nighttime movements about which she was unaware, a video camera was installed to monitor her moving actively at night. She slept in the living room, with a camera on and with a door alarm on in case she tried to leave. Due to concerns for her safety when she was active, she obtained a home health aide for three hours a day for a few months.

Mrs. CP found relief of her anxiety over one year’s time through weekly psychotherapy with a social worker and psychiatric follow-up every two to three weeks for medication management and support. She abruptly left for the Philippines at the end of that period to visit her family, and she moved in with one of her sons. Six months later, Mrs. CP returned to the United States and stated that she had stopped taking her medication while over in the Philippines. She described reduction in the frequency and intensity of her amnestic episodes. She continued to worry about her children and herself, especially because she felt that she was very forgetful at times. She continued to perform her activities of daily living successfully, living with her son and friend and not having deteriorated in her functioning. Mrs. CP decided to resume treatment for depression and anxiety, and so returned to the clinic.

The author reports no relevant financial relationships.

Dr. Woo is from Beth Israel Medical Center, New York, NY. Dr. Lantz is Chief of Geriatric Psychiatry, Beth Israel Medical Center, First Ave @ 16th Street #6K40, New York, NY 10003; (212) 420-2457; fax: (212) 844-7659; e-mail: mlantz@chpnet.org.


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