Dissociative Amnesia 301
disturbances. In dissociative amnesia, memory  deficits are primarily for autobiographical
information; intellectual and co gnitive abilities are preserved. 
Substance-related disorders. In the context of repeated intoxication with alcohol or
other substances/medications, there may be episod es of “black outs” or periods for which the
individual has no memory. To aid in distingu ishing these episodes from dissociative am-
nesia, a longitudinal history noting that the amnestic episodes occur only in the context of
intoxication and do no t 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 exac erbate dissociative symptoms. Some individuals with comor-
bid dissociative amnesia and substance use disorders will at tribute their memory prob-
lems solely to the substance use. Prolonged us e 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 co ntext the protracted history of  substance use and the persis-
tent deficits associated with the neurocognitive disorder would serve to distinguish it
from dissociative amnesia, wher e there is typically no evidence of persistent impairment in
intellectual functioning.
Posttraumatic amnesia due to brain injury. Amnesia may occur in th e context of a trau-
matic brain injury (TBI) when th ere has been an impact to th e head or other mechanisms of
rapid movement or displacement of the brain within the skull TBI. Other characteristics of
TBI include loss of consciousness, disorientati on and confusion, or, in more severe cases,