In DSM-III, this disorder is called Psychogenic Amnesia
A. Sudden inability to recall important personal information that is too extensive to be explained by ordinary forgetfulness.
In Organic Mental Disorders there is usually a memory disturbance whose onset has no relationship to stress and that is more marked for recent than for remote events. Memory impairment caused by organic factors usually disappears very slowly, if at all; full return of memory is rare. Furthermore, attention deficits, a clouding of consciousness, and disturbances of affect are frequently present.
In Substance-induced Intoxication there can be "blackouts" with failure to recall events that occurred during the intoxication. The organic factor (the substance taken) and the failure to achieve full return of memory clearly distinguish it from Psychogenic Amnesia.
In Alcohol Amnestic Disorder, short-term (not immediate) memory is impaired, i.e., events can be recalled immediately after they occur, but not after the passage of a few minutes. This type of memory disturbance is not seen in Psychogenic Amnesia. In addition, blunted affect, confabulation, and lack of awareness of the memory impairment are common in Alcohol Amnestic Disorder.
In postconcussion amnesia, the disturbance of recall, though circumscribed, is often retrograde, encompassing a period of time before the head trauma, whereas in Psychogenic Amnesia the disturbance of recall is almost always anterograde. Retrograde amnesia following head trauma can usually be distinguished from Psychogenic Amnesia by diagnostic use of hypnosis or an amytal interview; prompt recovery of the lost memories suggests a psychogenic basis for the disturbance.
In epilepsy, the memory impairment is sudden in onset, motor abnormalities are usually present during the episode, and repeated EEGs typically reveal anomalies.
In catatonic stupor, mutism may suggest Psychogenic Amnesia, but failure of recall is nearly always absent, and there usually are other characteristic catatonic symptoms, such as rigidity, posturing, and negativism.
Malingering involving simulated amnesia presents a particularly difficult diagnostic dilemma. Attention to the possibility that the amnesia is feigned plus careful questioning under hypnosis or during an amytal interview should help to resolve the dilemma.
A. The predominant disturbance is one or more episodes of inability 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, Posttraumatic Stress Disorder, Acute Stress Disorder, or Somatization Disorder 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).
C. The symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning.
Amnestic Disorder Due to a General Medical Condition, seizure disorders, delirium, and dementia
Dissociative Amnesia must be distinguished from Amnestic Disorder Due to a General Medical Condition, in which the amnesia is judged to be the direct physiological consequence of a specific neurological or other general medical condition (e.g., head trauma, epilepsy). This determination is based on history, laboratory findings, or physical examination. In Amnestic Disorder Due to a Brain Injury, the disturbance of recall, though circumscribed, is often retrograde, encompassing a period of time before the head trauma, and there is usually a history of a clear-cut physical trauma, a period of unconsciousness, or clinical evidence of brain injury. In contrast, in Dissociative Amnesia, the disturbance of recall is almost always anterograde (i.e., memory loss is restricted to the period after the trauma). The rare case of Dissociative Amnesia with retrograde amnesia can be distinguished by the diagnostic use of hypnosis; the prompt recovery of the lost memories suggests a dissociative basis for the disturbance. In seizure disorders, the memory impairment is sudden in onset, motor abnormalities may be present, and repeated EEGs reveal typical abnormalities. In delirium and dementia, the memory loss for personal information is embedded in a far more extensive set of cognitive, linguistic, affective, attentional, perceptual, and behavioral disturbances. In contrast, in Dissociative Amnesia, the memory loss is primarily for autobiographical information and cognitive abilities generally are preserved. The amnesia associated with a general medical condition usually cannot be reversed.
Memory loss associated with the use of substances or medications must be distinguished from Dissociative Amnesia. Substance-Induced Persisting Amnestic Disorder should be diagnosed if it is judged that there is a persistent loss of memory that is related to the direct physiological effects of a substance (e.g., a drug of abuse or a medication). Whereas the ability to lay down new memories is preserved in Dissociative Amnesia, in Substance-Induced Persisting Amnestic Disorder, short-term memory is impaired (i.e., events may be recalled immediately after they occur, but not after a few minutes have passed). Memory loss associated with Substance Intoxication (e.g., "blackouts") can be distinguished from Dissociative Amnesia by the association of the memory loss with heavy substance use and the fact that the amnesia usually cannot be reversed.
The dissociative symptom of amnesia is a characteristic feature of both Dissociative Fugue and Dissociative Identity Disorder. Therefore, if the dissociative amnesia occurs exclusively during the course of Dissociative Fugue or Dissociative Identity Disorder, a separate diagnosis of Dissociative Amnesia is not made. Because depersonalization is an associated feature of Dissociative Amnesia, depersonalization that occurs only during Dissociative Amnesia should not be diagnosed separately as Depersonalization Disorder.
In Posttraumatic Stress Disorder and Acute Stress Disorder, there can be amnesia or the traumatic event. Similarly, dissociative symptoms such as amnesia are included in the criteria set for Somatization Disorder. Dissociative Amnesia is not diagnosed if it occurs exclusively during the course of these disorders.
There are no tests or set of procedures that invariably distinguish Dissociative Amnesia from Malingering, but individuals with Dissociative Amnesia usually score high on standard measures of hypnotizability and dissociative capacity. Malingered amnesia is more common in individuals presenting with acute, florid symptoms in a context in which potential secondary gain is evident - for example, financial or legal problems or the desire to avoid combat, although true amnesia may also be associated with such stressors.
Care must be exercised in evaluating the accuracy of retrieved memories, because the informants are often highly suggestible. There has been considerable controversy concerning amnesia related to reported physical or sexual abuse, particularly when abuse is alleged to have occurred during early childhood. Some clinicians believe that there has been an underreporting of such events, especially because the victims are often children and perpetrators are inclined to deny or distort their actions. However, other clinicians are concerned that there may be overreporting, particularly given the unreliability of childhood memories. There is currently no method for establishing with certainty the accuracy of such retrieved memories in the absence of corroborative evidence.
Age-Related Cognitive Decline and nonpathological forms of amnesia
Dissociative Amnesia must also be differentiated from memory loss related to Age-Related Cognitive Decline and nonpathological forms of amnesia including everyday memory loss, posthypnotic amnesia, infantile and childhood amnesia, and amnesia for sleep and dreaming. Dissociative Amnesia can be distinguished from normal gaps in memory by the intermittent and involuntary nature of the inability to recall and by the presence of significant distress or impairment.
A. An inability to recall important autobiographical information, usually of a traumatic or stressful nature, that is inconsistent with ordinary forgetting. Note: Dissociative amnesia most often consists of localized or selective amnesia for a specific event or events; or generalized amnesia for identity and life history.
B. The symptoms cause clinically significant distress or impairment in social, occupational, or other important areas of functioning.
C. The disturbance is not attributable to the physiological effects of a substance (e.g., alcohol or other drug of abuse, a medication) or a neurological or other medical condition (e.g., partial complex seizures, transient global amnesia, sequelae of a closed head injury/traumatic brain injury, other neurological condition).
- With dissociative fugue: Apparently purposeful travel or bewildered wandering that is associated with amnesia for identity or for other important autobiographical information.
Individuals with dissociative amnesia may report depersonalization and auto-hypnotic symptoms. Individuals with dissociative identity disorder report pervasive discontinuities in sense of self and agency, accompanied by many other dissociative symptoms. The amnesias of individuals with localized, selective, and/or systematized dissociative amnesias are relatively stable. Amnesias in dissociative identity disorder include amensia for everyday events, finding of unexplained possessions, sudden fluctuations in skills and knowledge, major gaps in recall of life history, and brief amnesic gaps in interpersonal interactions.
Some individuals with PTSD cannot recall part or all of a specific traumatic event (e.g., a rape victim with depersonalization and/or derealization symptoms who cannot recall most events for the entire day of the rape). When that amnesia extends beyond the immediate time of the trauma, a comorbid diagnosis of dissociative amnesia is warranted.
In neurocognitive disorders, memory loss for personal information is usually embedded in cognitive, linguistic, affective, attentional, and behavioral disturbances. In dissociative amnesia, memory deficits are primarily for autobiographical information; intellectual and cognitive abilities are preserved.
In the context of repeated intoxication with alcohol or other substances/medications, there may be episodes of "black outs" or periods for which the individual has no memory. To aid in distinguishing these episodes from dissociative amnesia, a longitudinal history noting that the amnestic episodes occur only in the context of intoxication and do not occur in other situations would help identify the source as substance-induced; however the distinction may be difficult when the individual with dissociative amnesia may also misuse alcohol or other substances in the context of stressful situations that may also exacerbate dissociative symptoms. Some individuals with comorbid dissociative amnesia and substance use disorders will attribute their memory problems solely to the substance use. Prolonged use of alcohol or other substances may result in a substance-induced neurocognitive disorder that may be associated with impaired cognitive function, but in this context the protracted history of substance use and the persistent deficits associated with the neurocognitive diosrder would serve to distinguish it from dissociative amnesia, where there is typically no evidence of persistent impairment in intellectual functioning.
Posttraumatic amnesia due to brain injury
Amnesia may occur in the context of a traumatic brain injury (TBI) when there has been an impact to the head or other mechanisms of rapid movement or displacement of the brain within the skull TBI. Other characteristics of TBI include loss of consciousness, disorientation and confusion, or, in more severe cases, neurological signs (e.g., abnormalities on neuroimaging, a new onset of seizures or a marked worsening of a preexisting seizure disorder, visual field cuts, anosmia). A neurocognitive disorder attributable to TBI must present either immediately after brain injury occurs or immediately after the individual recovers consciousness after the injury, and persist past the acute post-injury period. The cognitive presentation of a neurocognitive disorder following TBI is variable and includes difficulties in the domains of complex attention, executive function, learning and memory as well as slowed speed of information processing and disturbances in social cognition. These additional features help distinguish it from dissociative amnesia.
Individuals with seizure disorders may exhibit complex behavior during seizures or post-ictally with subsequent amnesia. Some individuals with a seizure disorder engage in nonpurposive wandering that is limited to the period of seizure activity. Conversely, behavior during a dissociative fugue is usually purposeful, complex, and goal-directed and may last for days, weeks, or longer. Occasionally, individuals with a seizure disorder will report that earlier autobiographical memories have been "wiped out" as the seizure disorder progresses. Such memory loss is not associated with traumatic circumstances and appears to occur randomly. Serial electroencephalograms usually show abnormalities. Telemetric electroencephalographic monitoring usually shows an association between the episodes of amnesia and seizure activity. Dissociative and epileptic emnesias may coexist.
Mutism in catatonic stupor may suggest dissociative amnesia, but failure of recall is absent. Other catatonic symptoms (e.g., rigidity, posturing, negativism) are usually present.
There is no test, battery of tests, or set of procedures that invariably distinguishes dissociative amnesia from feigned amnesia. Individuals with factitious disorder or malingering have been noted to continue their deception even during hypnotic or barbiturate-facilitated interviews. Feigned amnesia is more common in individuals with 1) acute, florid dissociative amnesia; 2) financial, sexual, or legal problems; or 3) a wish to escape stressful circumstances. True amnesia can be associated with those same circumstances. Many individuals who malinger confess spontaneously or when confronted.
Memory decrements in major and mild neurocognitive disorders differ from those of dissociative amnesia, which are usually associated with stressful events and are more specific, extensive, and/or complex.