[7] Past literature[5] has suggested psychogenic amnesia can be 'situation-specific' or 'global-transient', the former referring to memory loss for a particular incident, and the latter relating to large retrograde amnesic gaps of up to many years in personal identity.
[5][11] The most commonly cited examples of global-transient psychogenic amnesia are 'fugue states', of which there is a sudden retrograde loss of autobiographical memory resulting in impairment of personal identity and usually accompanied by a period of wandering.
[12] There are many clinical anecdotes of psychogenic or dissociative amnesia attributed to stressors ranging from cases of child sexual abuse[13] to soldiers returning from combat.
[7] Psychological triggers such as emotional stress are common in everyday life, yet pure retrograde amnesia is considered very rare.
[19][20][21] Brain activity can be assessed functionally for psychogenic amnesia using imaging techniques such as fMRI, PET and EEG, in accordance with clinical data.
[7] Some research has suggested that organic and psychogenic amnesia to some extent share the involvement of the same structures of the temporo-frontal region in the brain.
[4] To reiterate however, care must be taken when attempting to define causation as only ad hoc reasoning about the aetiology of psychogenic amnesia is possible, which means cause and consequence can be infeasible to untangle.
[1] Treatments in the past have attempted to alleve psychogenic amnesia by treating the mind itself, as guided by theories which range from notions such as 'betrayal theory' to account for memory loss attributed to protracted abuse by caregivers[23] to the amnesia as a form of self-punishment in a Freudian sense, with the obliteration of personal identity as an alternative to suicide.
[14] However, information elicited from patients under the influence of drugs such as barbiturates would be a mixture of truth and fantasy, and was thus not regarded as scientific in gathering accurate evidence for past events.
[14] Hypnosis was also popular as a means for gaining information from people about their past experiences, but like 'truth' drugs really only served to lower the threshold of suggestibility so that the patient would speak easily but not necessarily truthfully.
Examples include William Shakespeare's King Lear, who experienced amnesia and madness following a betrayal by his daughters;[28] and the title character Nina in Nicolas Dalayrac's 1786 opera.