<unk>  or dissociative amnesia is a memory disorder characterized by sudden retrograde episodic memory loss, said to occur for a period of time ranging from hours to years to decades. More recently, "dissociative amnesia" has been defined as a dissociative disorder "characterized by retrospectively reported memory gaps. These gaps involve an inability to recall personal information, usually of a traumatic or stressful nature." In a change from the DSM-IV to the DSM-5, dissociative fugue is now subsumed under dissociative amnesia. The atypical clinical syndrome of the memory disorder (as opposed to organic amnesia) is that a person with<unk>  is profoundly unable to remember personal information about themselves; there is a lack of conscious self-knowledge which affects even simple self-knowledge, such as who they are.<unk>  is distinguished from organic amnesia in that it is supposed to result from a nonorganic cause: no structural brain damage or brain lesion should be evident but some form of psychological stress should precipitate the amnesia, however<unk>  as a memory disorder is controversial.
Psychogenic amnesia
Drug-induced amnesia
Excited delirium
Post-traumatic amnesia
Emergence delirium
Posthypnotic amnesia
Transient global amnesia
Memory distrust syndrome