Dissociation and the Fragmentary Nature of Traumatic Memories: Overview

Abstract

The nature and reliability of traumatic memories have been controversial issues in psychiatry for over a century. Traumatic memories are difficult to study, since the profoundly upsetting emotional experiences that may give rise to post-traumatic stress disorder (PTSD) and other trauma related outcomes cannot be approximated in a laboratory setting. For example, even viewing a movie depicting actual executions failed to precipitate post-traumatic symptoms in normal college students (Pitman, personal communication, 1994). If trauma is defined as the experience of an inescapable stressful event that overwhelms one's existing coping mechanisms, it is questionable whether findings of memory distortions in normal subjects exposed to videotaped stresses in the laboratory can serve as meaningful guides to understanding traumatic memories. Clearly, there is little similarity between viewing a simulated car accident on a TV screen, and being the responsible driver in a car crash in which one's own children are killed. While stress evokes homeostatic mechanisms that lead to self-conservation and resource-re-allocation (e.g. Selye 1956), PTSD involves a unique combination of learned conditioning, problems modulating arousal, and shattered meaning propositions. Shalev (1995) has proposed that this complexity is best understood as the co-occurrence of several interlocking pathogenic processes including (a) an alteration of neurobiological processes affecting stimulus discrimination (expressed as increased arousal and decreased attention), (b) the acquisition of conditioned fear responses to trauma-related stimuli, and (c) altered cognitive schemata and social apprehension.Without the option of inflicting actual trauma in the laboratory, there are limited options for the exploration of traumatic memories. These include collecting retrospective reports from traumatized individuals, post-hoc observations, and provoking, then studying, traumatic memories and flashbacks in people with PTSD. Surprisingly, since the early part of this century, there have been very few published studies that systematically explore the nature of traumatic memories based on detailed patient reports. Provocation studies of traumatic memories in the laboratory have examined psychophysiologic responses to visual or auditory stimuli (e.g. Pitman, Orr, Forgue, de Jong & Claiborn 1987; Rauch et al. 1995), and biological agents have been shown to promote access to trauma-related memories as well (Rainey et al. 1987;Southwick et al. 1993). This paper will first review studies of people's memories of highly stressful and of traumatic experiences, focusing on the differences between recollections of these two types of events. We will then review the evidence for dissociation as the central pathogenic mechanism that gives rise to PTSD. Finally, the results of a systematic exploratory study of 46 subjects who reported on their memories of childhood or adult trauma are presented and discussed.

Neurobiology of reconstructed memory.

“…This, of course, is exactly what is observed in the clinic and what has been reported from the laboratory. As described above, van der Kolk and Fisler (1995) presented evidence that memories of traumatic events are initially experienced as uncorrelated waves of feelings, images, or sensations without a coherent narrative memory for the traumatic events. Only subsequently do these memories take on an autobiographical character.…”

“…Traumatic levels of stress, however, simultaneously shut down the hippocampus-based system and facilitate the amygdala-based system, leading to the storage of emotional information unconnected to the contexts within which the relevant events occurred. Retrieval of this disconnected information, as we discuss in detail below, can produce disorganized, fragmented, and perhaps incomprehensible sense impressions and emotional memories (see, e.g., Thomas, Laurance, Jacobs, & Nadel, 1995;van der Kolk & Fisler, 1995). Development, Stress, and Memory Conjoined These notions about differential development and sensitivity to stress among various memory modules were at the root of our attempt to provide a neurobiological account of "irrational" fears and phobias (Jacobs & Nadel, 1985).…”

“…Controls reported no such intrusions. Van der Kolk and Fisler (1995) presented evidence that intrusive memories for traumatic events initially are fragmentary (or disaggregated) and organized nonverbally, as intense waves of feelings, visual images, olfactory, or auditory or behavioral sensations. Participants in this questionnaire-based study universally reported they initially remembered the trauma as uncorrelated affective, behavioral, or sensory flashbacks without a coherent narrative memory for the traumatic events.…”

“…L. Schacter, 1986;Sonnenberg, Blank, & Talbot, 1985;Southard, 1919;Thom& Fenton, 1920;van der Kolk & Kadish, 1987;Wilkinson, 1983;Williams 1994Williams , 1995. Trauma-induced amnesia appears related to age and to the intensity and duration of the trauma (see, e.g., van der Kolk & Fisler, 1995;and van der Kolk, McFarlane, & Weisaeth, 1996, for reviews).…”

Adaptação para a língua portuguesa do Questionário de Experiências Dissociativas Peritraumáticas (QEDP) numa amostra de bombeiros

“…Assim, as "recordações" do trauma são inicialmente experimentadas como fragmentos dos componentes sensoriais do acontecimento -tais como imagens visuais; sensações olfativas, audíveis ou cinestésicas; ou intensas ondas de sentimentos que os pacientes normalmente reclamam ser representações de elementos do acontecimento traumático original. Com efeito, os elementos sensoriais e emocionais do acontecimento podem não ser integrados na memória e na identidade pessoal e permanecerem isolados da consciência; a experiência é separada em elementos somatossensoriais isolados, sem integração numa narrativa pessoal 2 . Essa fragmentação é acompanhada por estados de ego que são distintos do estado normal de consciência.…”