Dissociative Amnesia
Dissociative amnesia is a sudden loss of memory, typically triggered by extreme psychological trauma, that can affect not only recent events but personal identity itself — name, address, and personal history. Strikingly, this occurs while the person's ability to carry out complex tasks and behave in a socially appropriate way remains intact, creating a notable gap between what is lost and what is preserved.
This has traditionally been distinguished by exactly this discrepancy: a marked loss of autobiographical memory occurring alongside a well-preserved personality and social competence, which is not the pattern usually seen in amnesia arising from organic brain disease.
Also known as
- Hysterical amnesia
- An older name for the same condition.
- Dissociative fugue
- A related presentation in which the amnesia is accompanied by sudden, purposeful travel away from home, with the person often found wandering in an unfamiliar place.
Recognition features
- Sudden onset of memory loss, typically following or during a period of extreme psychological trauma
- May affect personal identity itself, including name, address, and personal history, not just recent events
- Complex behaviours, social skills, and general functioning remain notably well preserved despite the memory loss
- May be accompanied by a fugue state, in which the person travels away from home and is found wandering, lost, in an unfamiliar place
Eliciting it at interview
- Explore the circumstances immediately preceding the onset of the memory loss, since a clear link to overwhelming psychological stress is a central feature
- Assess the extent of the amnesia carefully, including whether personal identity itself is affected, and compare this against the person's evidently preserved general functioning
- Take a history of prior head injury, since dissociative amnesia is more commonly reported in those with such a history
- Approach the possibility of malingering, particularly in a forensic context, with care and an open mind, since the distinction can be genuinely difficult to make
Distinguishing features
- Differs from organic amnesia in the striking preservation of complex skills and social behaviour alongside profound memory loss, including loss of personal identity
- Differs from catathymic amnesia in being broader, more sudden in onset, and capable of affecting identity itself, rather than being limited to a specific painful memory
- In a forensic context (someone charged with a serious offence), this presentation can be genuinely difficult to distinguish from malingering, and this distinction should be approached carefully rather than assumed
Common misconceptions
- That a person with dissociative amnesia must be exaggerating or faking, given the striking preservation of other abilities; this contrast is, in fact, a recognised and characteristic feature of the genuine condition
- That dissociative amnesia is the same as an organic memory disorder, only psychological in cause; the pattern of what is lost and preserved is often meaningfully different between the two
Related phenomena
Amnesia · Catathymic Amnesia · Hysterical Twilight State
Related defences
Diagnostically relevant to
Posttraumatic Stress Disorder (PTSD) (links open the DSM-5 Learning Lab)
Practice this
Following a violent assault, a woman is found wandering in an unfamiliar town, unable to recall her name, address, or any personal history, yet she has navigated public transport and interacted appropriately with several strangers along the way. What is this? · A young man involved in a serious road traffic collision, in which a close friend died, is unable to recall the collision itself or the weeks immediately surrounding it, though his memory for his life before and after that period is intact, and he successfully continues working and managing his daily responsibilities throughout. Before revealing the answer: is this dissociative amnesia? · A patient reports memory difficulty in the context of a mood or anxiety disturbance. Before revealing the answer, decide what distinguishes anxiety amnesia from dissociative amnesia. · A patient cannot recall a distressing part of her past. Before revealing the answer, decide what distinguishes catathymic amnesia from dissociative amnesia. · A patient presents with significant memory loss. Before revealing the answer, decide what distinguishes organic amnesia from dissociative amnesia. · You are assessing a patient with a sudden, apparently trauma-related memory loss and want to gather information supporting dissociative amnesia over an organic cause, without assuming the diagnosis. Which single approach is most appropriate? · A trauma survivor with sudden, dramatic memory loss continues to function well in complex daily tasks. Why does this combination support the diagnosis rather than suggesting the presentation is exaggerated?
Illustration
Three days after witnessing a violent assault, a 35-year-old woman is found wandering in a town over a hundred miles from home, unable to state her own name or recall anything about her life before that morning, yet she has been observed by police calmly purchasing a bus ticket and asking for directions in a manner entirely appropriate to the situation.
References
- Casey, P. & Kelly, B. (2019). Fish's Clinical Psychopathology, 4th ed. Ch. 5, 'Disorders of Memory'.