Questions and Answers REgarding Dissociative Amnesia
by Stephanie Dallam RN, MS, FNP
What is a traumatic memory?
A traumatic memory is a memory of personally traumatic event. For the purpose of diagnosing PTSD, a personally traumatic event is defined as:
What is dissociation?
Dissociation is a complex mental process during which there is a change in a person's consciousness which disturbs the normally connected functions of identity, memory, thoughts, feelings and experiences. Research has shown that individuals respond to overwhelming trauma by using a variety of psychological mechanisms. One of the most common means of dealing with the pain is to try and push it out of awareness.
Some label the phenomenon of the process whereby the mind avoids conscious acknowledgment of traumatic experiences as dissociative amnesia. Others use terms such as repression, dissociative state, traumatic amnesia, psychogenic shock, or motivated forgetting. Semantics aside, there is near-universal scientific acceptance of the fact that the mind is capable of avoiding conscious recall of traumatic experiences.
Is Dissociation Identity Disorder a valid diagnosis?
Gleaves, D. H., May, M. C., & Cardena, E. (2001). An examination of the diagnostic validity of dissociative identity disorder. Clinical Psychology Review, 21(4), 577.
Is dissociation a rare phenomenon?No. Scientific evidence shows that it is not rare for traumatized people to experience amnesia or delayed recall for the trauma. Amnesia has been reported in combat, for crimes, and for concentration camp experiences and torture. Evidence of this process can be found in the early literature on World War I and World War II.
One of the first reports in the scientific literature was by
Regarding "shell shock", he noted,
According to Myers, hypnosis was very effective in reversing the amnesia.
Rivers, W.H R. (1918). The repression of war experiences. Lancet, 194, 173-7.
Rivers regarded repression as a process of active, conscious exclusion of traumatic memories from awareness, -- suppression, stating, "It is natural to thrust aside painful memories just as it is natural to avoid dangerous or horrible scenes in actuality, and this natural tendency to banish the distressing is especially pronounced in those whose powers of resistance have been lowered by the long-continued strains of trench life, the shock of explosion, or other catastrophes of warfare . . ."
He also recognized that there was a social component - that people were motivated to forget bad things and other people reinforced this tendency. "[T]he natural tendency to repress being in my experience almost universally fostered by their relatives and friends, as well as by their medical advisers." (p. 173).
Thom, DA & Fenton, N. (1920). Amnesias in war cases. American Journal of Insanity, 76, 437-448.
Thom related the amnesia to dissociation. "There was no question of these soldiers being psychotic or neurotic prior to their loss of memory. All were considered desirable for military service." Further, Thom & Fenton recognized that the etiology of this amnesia was primarily psychic in origin - a finding confirmed by the fact that in two of these cases the memory was completely restored by the use of psychotherapy.
Sargent, W., & Slater, E. (1941). Amnesic syndromes in war. Proceedings of the Royal Society of Medicine, 34, 757-764.
In 1941, we see the first large scale study. Sargent and Slater examined the incidence of amnesia in 1,000 serial admissions to a military hospital.
Carlson, E., & Rosser-Hogan, R. (April, 1993). Mental health status of Cambodian refugees ten years after leaving their homes. American Journal of Orthopsychiatry, 63 (2), 223-231.
Dissociation is also a frequent finding in survivors extreme terror. Between 1975 and 1979, an estimated one to three million of a population of seven million Cambodians were killed or died of starvation. Carlson, E., & Rosser-Hogan selected 50 subjects at random from a list of all refugees (~500) resettled by nonprofit organization between 1983 and 1985. None had any formal education and had lived in the US for a mean of 5 years. 86% met the criteria for PTSD. The mean number of traumatic experiences the refugees endorsed was 14 and "90% reported amnesia for upsetting events." Mean DES score was 37.1 - which is extremely high compared to the mean score for the general population samples in the US - 8.6.
Krell, R. (1993). Child survivors of the Holocaust: Strategies of adaptation. Canadian Journal of Psychiatry, 38 , 384-389.
Krell reported on 22 Holocaust survivors who, as children, hid from the Nazis.
Marks, J. (1995). The hidden children: The secret survivors of the Holocaust. Toronto : Bantam Books.
One holocaust survivor, Ava Landy, describes her amnesia:
What types of traumas result in dissociative amnesia?
A review of 50 studies revealed that amnesia rates tend to increase with severity of trauma and is particularly high in victims of sex crimes.
What factors increase likelihood that the trauma will be forgotten?
There are several factors which influence whether a traumatic experience is remembered or dissociated.
The double-bind that children are placed in when a child suffers abuse at the hands of a caretaker, is discussed by Jennifer Freyd in her book on Betrayal Trauma . Freyd's theory explains how a blockage of information is functional, allowing a child who is abused by a parent to be able to ignore information that would otherwise interfere with their ability to function within an essential relationship.
Freyd found seven factors predict amnesia:
Freyd, Jennifer. (1996). Betrayal Trauma: The Logic of Forgetting Childhood Sexual Abuse. Cambridge, MA : Harvard University Press.
What is the relation of memory recovery to psychotherapy?
Albach et al. studied 97 adult victims of extreme sexual abuse and a control group of 65 women, matched for age and education who reported on their memories of "ordinary unpleasant childhood experiences." The abuse survivors were broken into two groups. One group had participated in psychotherapy while the other group had not. There was no significant differences in amnesia, memory recovery, or other memory phenomena between the survivors who participated in psychotherapy and those who did not.
Albach, F., Moormann, P. & Bermond, B. (1996). Memory Recovery of Childhood Sexual Abuse. Dissociation,9 (4), 261-273.
Wilsnack et al. studied a national probability sample of 711 women, aged 26 years to 54 years. 22% of respondents reported having sexually coercive experiences while growing up; of these, 69.0% indicated that they felt they had been sexually abused. More than one-fourth of respondents who felt sexually abused reported that they had forgotten the abuse for some period of time but later remembered it on their own. Only 1.8% of women self-described as sexually abused reported remembering the abuse with the help of a therapist or other professional person. The vast majority of memories were recovered in other contexts.
Wilsnack S. C., et al. (2002). Self-reports of forgetting and remembering childhood sexual abuse in a nationally representative sample of US women. Child Abuse & Neglect, 26, 139-147.
How accurate are recovered memories?
In a study by Williams, 129 women with documented histories of sexual victimization in childhood were interviewed 17 years later and asked about abuse history. 80 of the women recalled the victimization. However, 16% of those who recalled the abuse reported that at some time in the past they had forgotten about the abuse.
There were similar numbers of discrepancies in reports of women who had recovered memories and those who had always remembered compared to the reports from the early 1970s. Despite limited discrepancies, the women themselves were very often unsure about their memories and said things such as 'What I remember is mostly a dream.' Or, 'I'm really not too sure about this.' Level of uncertainty about recovered memories was not associated with more discrepancies in her account.
Williams, L. M. (1995). Recovered memories of abuse in women with documented child sexual victimization histories. Journal of Traumatic Stress, 8(4), 649-673.
Orr et al. examined abused women's physiologic responses during imagery of personal childhood sexual abuse experiences. The sample consisted of 71 women with a history of two or more episodes of sexual abuse prior to age 13. The investigators found that magnitudes of physiologic responses (i.e., heart rate, skin conductance, and electromyograms) during personal abuse imagery did not differ between those who recovered memories and those who had continuous memories. In addition, PTSD associated with continuous and recovered memories was found to be comparable.
Orr, S. P., Lasko, N. B., Metzger, L. J., Berry, N. J., Ahern, C. E., & Pitman, R. K. (1997). Psychophysiologic assessment of PTSD in adult females sexually abused during childhood. In R. Yehuda & A. C. McFarlane (Eds.), Psychobiology of Posttraumatic Stress Disorder. Annuals of the New York Academy of Sciences, Volume 821 . NY: The New York Academy of Sciences, pp. 491-3.
Dalenberg performed in depth family research including interviews and found the amount of evidence supporting continuous versus recovered memories were similar.
Dalenberg, C. J. (1996). Accuracy, timing and circumstances of disclosure in therapy of recovered and continuous memories of abuse. Journal of Psychiatry & Law,24 (2), 229-75.What is causes the memory to resurface?
What Triggers Recall of previously inaccessible memories of abuse?
A study by Albach et al. found that events that triggered recall of abuse included:
Sensory triggers included:
Albach, F., Moormann, P. & Bermond, B. (1996). Memory Recovery of Childhood Sexual Abuse. Dissociation, 9(4), 261-273.
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