Contrast TWO or more approaches to understanding the aetiology of Posttraumatic stress disorder

The notion of post-traumatic stress has been around since the latter half of the nineteenth century embedded in terms such as ‘shell shock’ and ‘combat neurosis’. However the official introduction of the term posttraumatic stress disorder (PTSD) in 1980 has instigated considerable research into the origins of the condition. Of course, such a disorder develops because the individual has been exposed to trauma of some kind. Indeed, the diagnostic criteria for PTSD uniquely includes an etiological element: “…the person has been exposed to a traumatic event…and the person’s response involved fear, helplessness and horror” (DSM-IV; American Psychiatric Association, 1994). Here lies a misconception that the aetiology of PTSD is known as the disorder is seen as a pathological response to trauma. However, investigators have questioned why it is then that not all people of similar circumstances go on to develop the disorder and consequently have searched for a more thorough understanding of the aetiology of posttraumatic stress (Jones & Barlow, 1990). Many perspectives have contributed, including the biological, but the psychological, especially the cognitive paradigm has indoctrinated the field of PTSD with numerous theories. These cognitive theories all propose that for an individual the event of trauma provides information that is incongruent with pre-existing beliefs about the world and that unsuccessful attempts to incorporate this novel information into existing models can lead to posttraumatic stress. However each theory differs in how and to what extent they account for the accumulating knowledge about PTSD. In drawing upon these differences, this essay will contrast three cognitive theories of PTSD: Horowitz’s (1986) stress response theory; Foa and colleagues’ (1986; 1989) fear network theory; Brewin, Dalgleish, and Joseph’s (1996) dual representation theory.

Many would agree that the experiencing of extreme catastrophic events, such as earthquakes, hurricanes and concentration camps is quite rare. However, most of us like to think of ourselves as living in a protective bubble, where we are even invulnerable to the more everyday tragedies of sexual assaults, car accidents and muggings. In recent years, careful analysis has generated the recognition that such events can have devastating and long-lasting effects on the individuals involved. These reactions to traumatic events can be indicative of a post-traumatic stress disorder.

As described in the ‘Diagnostic and Statistical Manual of Mental Disorders’ (DSM-IV; American Psychiatric Association, 1994), there are various phenomena that characterise the posttraumatic reaction. For example, PTSD patients are described as “psycho-physiologically hyperaroused” (Joseph, Williams, & Yule, 1997, p. 8) and often display startle responses and hypervigilance. However many consider the oscillation between re-experiencing and avoiding of trauma-related memories suffered by PTSD patients to be the hallmark characteristic of the disorder. The memories frequently consist of images and intrude into consciousness, simultaneous to the reproduction of the intense emotions that occurred during the trauma. Thus, there is a re-enactment of the original trauma, where the individual mentally and physically re-experiences the trauma. The persistent experience of these ‘flashbacks’, in turn causes the individual to engage in persistent avoidance of things associated with the trauma, as seen in the emotional numbing and restricted affect displayed by many post trauma, subsequently leading to a constant fluctuation between the two states (Brewin, Dalgleish, & Joseph, 1996). Within the domain of posttraumatic stress disorder research as a whole, there is a consensus among theoreticians that a thorough conceptualisation of PTSD and its aetiology must account for the clinical characteristics of the disorder, especially this constellation of symptoms that encompass the disorder. The cognitive accounts, although similar in some respects, have approached this task in different ways.

In Horowitz’s (1986) early theory of stress-response syndromes, for example, the flashbacks that are characteristic of the disorder are seen as a consequence of delayed cognitive processing of thoughts, memories and images of the trauma. A combination of an inherent psychological need to integrate new information with the existing mental models of the world (completion tendency), and the fact that trauma-related information is very often incongruent with them, leads to a stress response requiring re-assessment of the mental models. Generally large alterations in such schema are necessary after exposure to severely traumatic events. Consequently complete integration and cognitive processing take ...

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According to the theory, active memory is inclined to repeat its representations of the traumatic event, which overwhelms the individual’s capacities to cope and subsequently results in emotional distress. The consequent initiation of an inhibitory regulatory system paces the absorption of the traumatic information, but if weak, inhibitory control can cause the emergence of the re-experiencing flashback episodes. When inhibitory efforts are too strong in relation to the events in active memory, attempts are made to avoid things associated with the trauma, giving rise to the distinctive oscillation between intrusion and avoidance phases in individuals with posttraumatic stress (Joseph, Williams and Yule, 1997).

In contrast to this social cognitive framework implemented by Horowitz, where in explaining the complex phenomenology of PTSD, emphasis is placed upon the impact of the trauma on a wider personal and social level, are the cognitive theories that target the traumatic event itself, specifically the trauma-related threat. This information, it is asserted, is represented in memory in a special way and if not correctly processed will formulate as psychopathology in the individual (Brewin & Holmes, 2003).

One such information processing approach has been put forward by Foa and her colleagues (Foa & Kozak, 1986; Foa, Steketee, & Rothbaum, 1989). Here, it is postulated that post-trauma, stimulus information about the traumatic event; information regarding cognitive, behavioural and physiological responses to the trauma; and information linking these stimulus and response elements, is uniquely represented in a fear network in memory. According to this early network theory, when the individual encounters stimuli reminiscent of the event, these selectively activate the fear network in memory, causing the arousal symptoms of PTSD, such as hypervigilance, and information in the network to enter consciousness (the intrusion symptoms of PTSD). The avoidance symptoms of PTSD are seen as a result of subsequent attempts made by the individual to repress such activation and intrusion. The successful endpoint of this emotional processing of trauma is the integration of the information within the fear network with the person’s hitherto memory structures and can be achieved by the weakening of the strong associations within the network. Information that is contradictory to that within the fear network is the suggested means of attaining such integration. However Foa and her group of researchers stress that factors such as the lack of predictability and controllability of the traumatic experience can impede successful integration, as the existing models of the world into which trauma information attempts to be integrated, assumes a predictable and controllable world.

Like Horowitz, the notion that there is normally a period of emotional processing following trauma, that can give rise to PTSD phenomenon such as flashbacks is also advocated by Foa et al (1986; 1989). However this information processing account has alternative opinions to Horowitz and the social-cognitive approaches in general, regarding the exact nature of the intrusive memories and the underlying mechanisms that drive emotional processing. Whereas it is the incongruent relation between the trauma information and the individual’s pre-existing assumptions about the world that gives rise to intrusive thoughts and images of the trauma in stress response theory, in the fear network approach more detailed sensory and physiological information concerning the event emerges as a result of the activation of traumatic memories by problematic cues (Brewin et al, 1996).

Recently, Brewin et al (1996) in a somewhat novel approach to understanding the aetiology of posttraumatic stress disorder, collaborate with the largely conscious emotional processing of trauma, but attempt to combine the two differing accounts of this process provided by the social-cognitive and information processing approaches outlined above in their own dual representation theory. As indicated by the name, this theory postulates that Foa’s (1986; 1989) “…concept of a single emotional memory does not appear adequate to capture the full range of observed phenomena…for example, the distinction between verbally retrievable memories and flashbacks” (Brewin et al, 1996, p.675-676), and in fact there is dual representations of a single traumatic experience in memory. Largely attributable to extensive research, suggesting the conscious and non-conscious processing of sensory input, the dual representation theory advocates the parallel operation of two memory systems, but highlights that one can take superiority over the other at different times.

A ‘verbally accessible memory’ (VAM) system consists of trauma memories that contain information that received the adequate amount of conscious processing for it to be passed on to a long-term memory store and deliberately accessed later on, especially for verbal communication with others. These VAMs register one of two elements of the emotional processing of trauma proposed by Brewin et al (1996). Similar to Horowitz’s social-cognitive description, this is the conscious attempt to understand the conflicting information supplied by the trauma by evaluating the event and searching for meaning and cause. Thus, in addition to primary emotions that were experienced during the trauma, VAMs are also accompanied by secondary emotions, such as guilt and anger, which may be produced by looking back and making attributions about responsibility.

Flashbacks, however, are thought to be indicative of the workings of a ‘situationally accessible memory’ (SAM) system. This term is specifically used because flashbacks reflect the representation of the trauma that originates from non-conscious processing of the event, which cannot be deliberately accessed but instead are only ever triggered involuntarily when the individual is faced with situational reminders (physical features or internal meaning) of the trauma. This SAM system stores perceptually orientated information about the trauma environment, such as sights, smells and sounds. Furthermore is the storage of information related to physiological responses to the trauma, such as pain and changes in heart rate, resulting in the qualitative difference between flashbacks and deliberately retrievable memories. This highlights the second element of the dual representation’s approach to the emotional processing of trauma. Reflecting the information processing approach of fear network theory, this involves the stimulation of the SAMs in order to provide the detailed sensory and physiological information concerning the event as a means of initiating cognitive assimilation. Thus, SAMs are associated with only so called primary emotions (i.e. fear and horror), as they are those that were experienced at the time of the trauma (Brewin & Holmes, 2003).

So, in contrast to Foa et al’s approach to understanding the aetiology of PTSD, the dual representation theory, by distinguishing between VAMs and SAMs, is not limited to explaining only the common intrusion, avoidance and arousal symptoms, but also other observed clinical phenomena such as the qualitative distinction between verbally retrievable memories of the trauma and flashbacks. Unlike network models and their single level of representation, the notion of a dual representation of trauma memory is able to distinguish between remembering an event in a dispassionate, cool manner on the one hand, and in a more emotionally burdened hot way on the other (Brewin & Holmes, 2003). Furthermore, in terms of the emotional processing of trauma, the innovative distinction between SAMs and VAMs and the accompaniment of primary and secondary emotions respectively is again able to excel the fear network theories, by accounting for additional clinical characteristics of PTSD. These are the negative emotions and cognitions, such as sadness and guilt (secondary emotions) that often accompany the disorder.

In explicitly addressing these secondary emotions, dual representation theory highlights the existence of factors that are likely to influence the outcome of emotional processing. Indeed there are many variables that are known to be associated with the development and maintenance of PTSD and as emphasised by Jones and Barlow (1990), any theory on PTSD should also incorporate these, especially as there is a need to explain the lack of symptoms in some trauma experienced individuals. In the dual representation account the aversive secondary emotions are a result of making attributions about responsibility. Although Foa et al (1986; 1989) have also highlighted the important role of the individual’s attributions and analysis of the traumatic event by emphasising the predictability and manageability of the trauma, in contrast as criticised by Brewin et al (1996, p. 674) “Horowitz’s theory is somewhat passive. Little credit is given to the power of the individual’s attributions and interpretations of the traumatic experience and the effect that these have on outcome.”

Three possible outcomes of the period of emotional processing are distinguished in the dual representation theory. Firstly is the successful integration of trauma memories with the person’s other existing memories and sense of existence in the world. Here Brewin and colleagues account for the adaptive role of social support, another known predictor of severity and chronicity of symptoms. Successful integration, they propose, involves the reduction of negative effect, where by providing physical comfort and emotional support, social support has a central role. Although a similar buffering effect of social support is accounted for in fear network theory, by indicating a role for it in the provision of incompatible information to aid successful processing, it is not adequately done so in Horowitz’s account as he highlights this process but doesn’t fully explain it’s precise operation (Brewin et al, 1996).

The presence of secondary aversive emotions, as noted above can have an effect on the outcome of the emotional processing of trauma. They are very likely to prevent the individual from effectively processing the memories of trauma and therefore contribute to an unwanted outcome of chronic emotional processing. The third viable outcome according to the dual representation explanation of PTSD is the premature inhibition of processing as a consequence of consistent repetition of avoiding strategies resulting in the process becoming involuntary. Although this will bring conscious emotional processing to a standstill, the outcome of complete integration does not result as one would assume, but instead a state of inhibited processing, as SAMs of trauma are still accessible under the right conditions. This innovative feature of the dual representation theory, unlike the stress response and fear network approaches, enables it to adequately account for additional clinical characteristics of PTSD. This is its varied time course, occasional delayed onset and the recommencing of emotional processing months or even years after apparent cessation.

In summary, the social cognitive approach taken by Horowitz (1986) in his stress response theory of PTSD can be contrasted with the more information processing orientated account offered by Foa et al (1986; 1989) in their theory centred around the formation of a fear network in memory post trauma. By implementing different facets of the cognitive paradigm, they account for the complex symptomology of PTSD in related but distinct ways. Brewin et al’s (1996) dual representation theory synthesises these two accounts into one overarching framework and introduces a minimum cognitive architecture for which PTSD must be understood (VAMs and SAMs). Consequently, in addition to the common symptoms, this theory, unlike the others, also explains other known clinical characteristics of PTSD (e.g. secondary emotions). Following this, the dual representation theory, arguably is the more comprehensive account of the three as it seems to address, more so than the others, most of the accumulating knowledge about the psychiatric disorder, including a varied course and variables associated with its severity and outcome. Indeed, Jones and Barlow’s (1990) main criteria for which to assess the adequacy of an etiological model, that is, an explanation of why some individuals rather than others exposed to similar trauma go on to develop PTSD, is addressed by dual representation theory. In distinguishing between three outcomes of emotional processing and also a general response to trauma versus processes that are more specific to PTSD, the presence of intrusive memories post severe trauma can be viewed as a normal reaction, but months of continual emotional processing as a more chronic failure to resolve discrepancies. However, it must be mentioned that dual representation’s superiority in accounting for more of the existing knowledge about PTSD is probably largely attributable to the fact that it is the most recent of the three, and it is in the decade between the emergence of it and the earlier accounts that the vast amount of knowledge has accumulated. Furthermore, as highlighted throughout this discussion, Horowitz and Foa’s ideas did indeed lay the foundations for the later development of the dual representation approach to understanding the aetiology of PTSD.

References

American Psychiatric Association (1994). Diagnostic and statistical manual (4th ed.). Wasington, DC: Author.

Brewin, C., Dalgleish, T. & Joseph.S. (1996). A Dual Representation Theory of Posttraumatic Stress Disorder. Psychological Review,103, 670-686.

Brewin, C.R. & Holmes, E.A.. (2003). Psychological theories of posttraumatic stress disorder. Clinical Psychology Review, 23, 339-376.

Foa, E.B. & Kozak, M.J. (1986). Emotional Processing of fear: Exposure to corrective information. Psychological Bulletin, 90, 20-35.

Foa, E.B., Steketee, G. & Rothbaum, B.O. (1989). Behavioural/cognitive conceptualisation of post-traumatic stress disorder. Behaviour Therapy, 20, 15-176.

Horowitz, M.J. (1986). Stress response syndromes. (2nd ed.). New York: Jason Aronson.

Jones, J.C. & Barlow, D.H. (1990). The etiology of posttraumatic stress disorder. Clinical psychological review, 10, 299-328.

Joseph, S., Williams, R. & Yule, W. (1997). Understanding Post-traumatic stress: A psychosocial perspective on PTSD and treatment. (1st ed.). England: John Wiley & Sons Ltd.