Dissociative identity disorder. Individuals with dissociative amnesia may report de- personalization and auto-hypnotic symptoms. Individuals with dissociative identity dis- order 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 iden- tity disorder include amnesia 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.
Posttraumatic stress disorder. 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 amne- sia extends beyond the immediate time of the trauma, a comorbid diagnosis of dissociative amnesia is warranted.
Neurocognitive disorders. In neurocognitive disorders, memory loss for personal infor- mation 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.
Substance-related disorders. 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 am- nesia, 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 sub- stance-induced; however the distinction may be difficult when the individual with dis- sociative amnesia may also misuse alcohol or other substances in the context of stressful situations that may also exacerbate dissociative symptoms. Some individuals with comor- lems 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 cog- nitive function, but in this context the protracted history of substance use and the persis- tent deficits associated with the neurocognitive disorder 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 trau- matic 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 im- mediately 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 func- tion, learning and memory as well as slowed speed of information processing and distur- bances in social cognition. These additional features help distinguish it from dissociative amnes1a.