Dysfunctional meaning of posttraumatic intrusions in chronic PTSD

Abstract

The paper suggests that the negative idiosyncratic meaning of posttraumatic intrusions (e.g., ‘I am going crazy’) and cognitive strategies intended to control the intrusions play a major role in maintaining posttraumatic stress disorder. Two studies of 159 and 138 motor vehicle accidents survivors showed that the dysfunctional meaning of intrusions explained a proportion of the variance of the intrusion-related distress, strategies used to end the intrusions, and PTSD severity that was not explained by intrusion frequency, accident severity, or by general catastrophic thoughts when anxious. Rumination, thought suppression, and distraction when having intrusions showed substantial correlations with PTSD severity, as did avoidance of reminders of the accident. The results have implications for the treatment of chronic PTSD.

Introduction

Intrusive recollections of aspects of a traumatic event and its sequelae are at the core of posttraumatic stress disorder (PTSD). Reexperiencing can take the form of images, or other sensory impressions such as noises, smells, tactile sensations, thoughts, flashbacks, or dreams. These symptoms distinguish PTSD from the other anxiety disorders. The present paper is concerned with involuntary memories or thoughts which are related to the trauma or its consequences. Trauma-related phenomena occurring during sleep are not considered because it is possible that different mechanisms are involved in their development and/or maintenance.

Reexperiencing symptoms that occur immediately after a trauma are generally considered a sign of normal adaptation (Eberly et al., 1991, Rachman, 1990). In line with this assumption, prospective studies have found that the experience of intrusive recollections immediately after the trauma is often not a good predictor of persistent PTSD (McFarlane, 1988, Perry et al., 1992, Shalev, 1992). On the other hand, intrusive reexperiencing that persists for several months has been shown to predict long-term PTSD symptoms (Baum et al., 1993, McFarlane, 1992, Perry et al., 1992). This difference indicates that it is important to distinguish between factors that determine initial reexperiencing symptoms, and those involved in their maintenance.

Although theoretical models of PTSD etiology and maintenance vary widely, there is general agreement that avoidance of reminders of the trauma is a central factor in maintaining PTSD symptoms. It prevents adequate emotional processing of traumatic experiences as well as habituation to traumatic memories. It interferes with integration and restructuring of dysfunctional cognitions concerning the trauma (Chembtob et al., 1988, Foa et al., 1989, Foa and Riggs, 1993, Horowitz, 1976, Jones and Barlow, 1990, Keane et al., 1985, Pennebaker, 1989, Van der Kolk and van der Hart, 1991). Avoidance has been found to be involved in the long-term maintenance of intrusive phenomena in PTSD and in other anxiety disorders (Lawrence et al., 1996, Salkovskis and Kirk, 1989).

PTSD patients engage in a wide range of avoidance behaviors. Cognitive avoidance strategies seem to be especially common, but have not yet been investigated in sufficient detail. Clinical observation shows that PTSD patients commonly report to use thought suppression, a cognitive activity designed to avoid or end particular thoughts, images, or memories. Research has demonstrated that, paradoxically, thought suppression increases the probability of intrusive phenomena in other anxiety disorders, for example obsessional compulsive disorder and generalized anxiety disorder (Lavy and van den Hout, 1994, Salkovskis and Campbell, 1994). Heightened attention to and monitoring of intrusive memories may similarly increase the probability of their occurrence.

Many patients with PTSD report ruminating extensively, for example about why the trauma happened to them. Rumination appears to be another cognitive avoidance strategy in that it focuses on experiences surrounding the traumatic event rather than the event itself. Borkovec and Inz (1990) proposed that rumination, as a predominantly verbal activity, is used to avoid physical and emotional reactions towards unpleasant and anxiety-provoking images. Wells (1994) postulated that rumination blocks emotional processing of distressing experiences and concurrently connects these experiences to many other stimuli, thereby enhancing their accessibility in memory networks. Ehlers and Steil (1995) suggested that rumination may be one of the major strategies of cognitive avoidance in chronic PTSD.

What determines who engages in cognitive and behavioral avoidance is as yet unclear. An important observation in this context is that, while posttraumatic intrusions are common in the immediate aftermath of trauma, not all survivors find these intrusions distressing (Shalev, Schreiber & Galai, 1993). This finding echoes results showing that it is distress caused by obsessional intrusions, not their occurrence per se, which distinguishes clinical from nonclinical populations (Rachman & de Silva, 1978). Traumatized individuals who experience intrusive recollections of the trauma as distressing are more likely to attempt to avoid or suppress them than those who do not find them distressing. The hypothesis that intrusion-related distress is an important determinant of long-term outcome is supported by findings that initial distress caused by intrusive memories of motor vehicle accidents (MVA) predicted PTSD severity 12 months later (Mayou, Bryant & Duthie, 1993).

What determines the degree of distress caused by posttraumatic intrusions? Trauma severity has been shown to be associated with PTSD severity. Aspects of the traumatic event such as injury severity, witnessed death or injury and threat to life have been found to influence the development of PTSD symptoms (Creamer et al., 1992, Yehuda et al., 1992). It is quite likely that these factors are associated with the distress caused by persistent posttraumatic intrusions. However, it is doubtful that they are significant determinants of intrusion-related distress in the longer term.

In the maintenance of other anxiety disorders, cognitive factors such as the interpretation of particular symptoms have been found to play a central role (Clark, 1986, Ehlers et al., 1988, Salkovskis and Kirk, 1989). In panic disorder, for example, misinterpretation of bodily sensations (e.g., ‘I am going to lose control’ or ‘This means that something terrible will happen’) is believed to determine engagement in safety behaviors and avoidance, and so maintain the disorder. Similarly, several authors have suggested that patients with PTSD interpret PTSD-symptoms in a dysfunctional way (e.g., ‘If after all of this time I react to memories of the event in such a strong way there must be something wrong with me!’, e.g., Foa et al., 1989, Foa and Riggs, 1993, Jones and Barlow, 1990, Peterson et al., 1991). In particular, misinterpretation of symptoms of arousal has been a focus in the PTSD literature.

Ehlers and Steil (1995) have proposed that the negative idiosyncratic meaning of intrusive symptoms is important in the maintenance of PTSD. Dysfunctional meanings concern both the occurrence of intrusions (e.g., ‘The fact that I have these uncontrollable memories means that I am going crazy’) and their content (i.e., the traumatic events and its sequelae). Examples of the latter are ‘My life is ruined’, ‘It was my fault’, and ‘It will happen again’.

The authors suggest two pathways by which dysfunctional meanings maintain posttraumatic intrusions and other PTSD symptoms. They are assumed (1) to determine the degree of distress, and thus arousal, caused by intrusions, and (2) to determine the extent of cognitive and behavioral avoidance.

Fig. 1 illustrates the proposed associations between the negative idiosyncratic meaning assigned to trauma and posttraumatic symptomatology. The ‘distress’ pathway leads to short-term maintenance of arousal and reexperiencing symptoms. Distress caused by the negative meaning of the intrusions is likely to be accompanied by physical symptoms such as heightened arousal, difficulties sleeping, and poor concentration (1). Physical arousal in turn can act as an internal trigger for the occurrence of intrusions (2). Furthermore, intense distress and arousal may confirm the negative meaning (3) the intrusions have for the individual (e.g., ‘I am incompetent’).

The ‘avoidance’ pathway leads to the maintenance of posttraumatic intrusions in the short and long term. The dysfunctional meaning of the intrusions motivates the individual to engage in behavioral and cognitive avoidance strategies intended to bring the intrusions to an end (4). The increase in upset and arousal which is connected to the occurrence of intrusions may contribute to the motivation to avoid these experiences (5). As described above, cognitive strategies like thought suppression and rumination actually lead to increased intrusion frequencies (6). The individual may perceive the paradoxical effects of cognitive avoidance strategies as alarming. These strategies might therefore contribute to the level of distress caused by posttraumatic intrusions (‘Although I try very hard to get rid of these memories, they keep coming back to me!’). Furthermore, these strategies might directly be related to symptoms of heightened arousal like difficulties sleeping or concentrating (7). Avoidance of reminders of the trauma prevents reduction in distress/arousal (habituation). It prevents change in meaning of the intrusions and the trauma (8) and thus maintains the intrusions in the long term.

Two studies on survivors of motor vehicle accidents were conducted to empirically test hypotheses derived from the model. Specifically, it was hypothesized that the dysfunctional meaning of posttraumatic intrusions shows substantial correlations with:

• Distress caused by posttraumatic intrusions;

• Behavioral and cognitive avoidance (avoidance of reminders, rumination, thought suppression, distraction);

• PTSD symptom severity,

which are not mediated by objective or subjective accident severity, intrusion frequency, or general dysfunctional cognitions when anxious.

It was further hypothesized that:

4. Intrusion-related distress, and behavioral and cognitive avoidance would show substantial correlations with PTSD severity.