Peritraumatic dissociation and experiential avoidance as predictors of posttraumatic stress symptomatology

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Abstract

This study examined whether peritraumatic dissociation serves as a proxy risk factor for experiential avoidance in its relationship with posttraumatic stress disorder (PTSD) symptomatology. One hundred eighty-five trauma survivors completed measures that assessed for peritraumatic dissociation, experiential avoidance, and PTSD symptom severity. The results indicated that peritraumatic dissociation and experiential avoidance were significantly related to PTSD symptomatology at baseline. However, after initial levels of PTSD symptomatology were taken into account, only experiential avoidance was related to PTSD symptoms both 4- and 8-weeks later. These results indicate that peritraumatic dissociation is not a proxy risk factor for experiential avoidance and contributes to the growing body of literature indicating that experiential avoidance is an important factor related to the psychological symptoms experienced by trauma survivors.

Introduction

Previous research has noted a relationship between trauma and dissociative behavior (e.g., Bremner et al., 1992; Cardena & Spiegel, 1993; Chu & Dill, 1990; Dancu, Riggs, Hearst-Ikeda, Shoyer, & Foa, 1996; Koopman, Classen, & Spiegel, 1994; Wagner & Linehan, 1998). One important aspect of the dissociative response to trauma is the dissociation that occurs during the traumatic event, referred to as peritraumatic dissociation. Peritraumatic dissociation has received much attention in recent years because it has been shown to be a significant risk factor for the development of posttraumatic stress disorder (PTSD) and other psychological symptomatology following exposure to trauma (Birmes et al., 2003; Bremner et al., 1992; Koopman, Classen, & Spiegel, 1994; Marmar et al., 1994; Ozer, Best, Lipsey, & Weiss, 2003; Shalev, Peri, Canetti, & Schreiber, 1996). Although peritraumatic dissociation has been identified as a risk factor for PTSD, the mechanism through which this dissociation might make one susceptible to PTSD is not well understood.

Some researchers have suggested that the relationship between peritraumatic dissociation and PTSD may be mediated by high levels of anxiety experienced during the trauma (Krystal, Woods, Hill, & Charney, 1991; Marmar, Weiss, & Metzler, 1997; Moleman, van der Hart, & van der Kolk, 1992; Southwick et al., 1993). This hypothesis was tested by Gershuny, Cloitre, and Otto (2003) who examined the hypothesis that the relationship between peritraumatic dissociation and PTSD symptoms was mediated by fears of death and loss of control. Using a sample of undergraduate females with a trauma history, results showed that the proposed mediators did, in fact, account for the relationship between peritraumatic dissociation and PTSD severity. However, given the cross-sectional nature of the investigation, an alternate model specifying a different relationship among the variables is plausible; that is, peritraumatic dissociation may mediate the relationship between fears of death and losing control and posttraumatic stress.

In another investigation, Marshall and Schell (2002) prospectively examined the relationship between peritraumatic dissociation and PTSD symptom severity. Using a cross-lagged panel analysis of longitudinal data collected from survivors of community violence, the investigators showed that peritraumatic dissociation was significantly correlated with PTSD symptoms at both 3- and 12-month follow-up interviews. Although the investigators did not specifically investigate anxiety as a mediator of the relationship between peritraumatic dissociation and PTSD, they did find that baseline peritraumatic dissociation did not predict subsequent PTSD symptom severity after controlling for baseline PTSD symptom severity.

Taken together, these findings suggest that the nature of the relationship between peritraumatic dissociation and PTSD is still unclear. In an attempt to further elucidate the relationship between peritraumatic dissociation and PTSD, some investigators have proposed that dissociative behavior is a form of experiential avoidance (e.g., Hayes, Wilson, Gifford, Follette, & Strosahl, 1996; Polusny & Follette, 1995). Experiential avoidance is defined as the unwillingness to remain in contact with aversive private experiences (i.e., bodily sensations, emotions, thoughts, memories, behavioral predispositions), as well as the steps taken to alter the form or frequency of those events and the contexts that occasion them. In line with this formulation, Wagner and Linehan (1998) suggested that the principle function of peritraumatic dissociation is to regulate particular aspects of the trauma (e.g., aversive stimuli and affect) as it is occurring in an attempt to cope with the experience. Others have also suggested that dissociative behavior serves to avoid unwanted emotions, thoughts, and memories (Foa & Hearst–Ikeda, 1996; Foa & Riggs, 1993; Horowitz, 1986; van der Kolk et al., 1996).

Investigators have suggested that such attempts to avoid unwanted emotions, thoughts, memories, and sensations may initially decrease the frequency and severity of such private events. Ultimately, however, the avoidance attempts result in increases in these same private experiences (Hayes, Wilson, Gifford, Follette, & Strosahl, 1996; Hayes, Wilson, & Strosahl, 1999; Polusny & Follette, 1995). This position is consistent with the finding that attempts to control internal events often lead to increases in the internal events that one is attempting to control (Cioffi & Holloway, 1993; Clark, Ball, & Pape, 1991; Gold & Wegner, 1995; Hayes, Wilson, Gifford, Follette, 1996; Kelly & Kahn, 1994; Muris, Merckelback, van den Hout, & de Jong, 1992; Salkovskis & Campbell, 1994; Wegner, 1994; Wegner & Zanakos, 1994; Wenzlaff & Wegner, 2000), which further results in perpetual and futile attempts to control these internal experiences. Importantly, attempts to distance oneself from unwanted private experiences appear to result in psychological and behavioral difficulties (e.g., substance use, anxiety, depression, suicidal behavior, risk-taking, aggressive behaviors; Hayes, 1987; Hayes, Wilson, Gifford, Follette, & Strosahl, 1996, Marx & Sloan, 2002). In other words, psychological and behavioral difficulties are the manifestation of attempts to control, avoid, and/or suppress aversive private events. In this framework then, the PTSD symptomatology (i.e., re-experiencing, avoidance and emotional numbing, and hyperarousal) suffered by some trauma survivors may be the by-product of the experiential avoidance process.

Researchers have tested the hypothesis that individuals with trauma histories engage in experiential avoidance and that such avoidance is related to psychological symptomatology. For instance, Marx and Sloan (2002) hypothesized that experiential avoidance and emotional expressivity would mediate the relationship between a history of childhood sexual abuse (CSA) and psychological distress. To test this hypothesis, college undergraduates completed measures that assessed for a CSA history, experiential avoidance, emotional expressivity, and psychological functioning. The findings indicated that CSA status, experiential avoidance and emotional expressivity were significantly related to psychological distress. However, only experiential avoidance mediated the relationship between CSA status and distress. These findings are consistent with those reported by Batten, Follette, and Aban (2001) who also showed that CSA survivors engage in experiential avoidance as well as with the results of a study conducted by Tull and Roemer (2003) who, using a sample of female sexual assault survivors, found that experiential avoidance accounted for a significant portion of the variance in PTSD symptomatology. Overall, these studies contribute to the growing body of literature indicating that experiential avoidance has an influential role in the development and maintenance of psychological symptoms among trauma survivors.

The implication of this previous theoretical and empirical work is that peritraumatic dissociation may only have a relationship with PTSD symptomatology as a result of its relationship with experiential avoidance. Indeed, other investigators have noted the relationship between dissociative responses during the trauma and more pervasive avoidance coping styles (Marmar, Weiss, Metzler, & Delucchi, 1996; Marmar et al., 1996). As such, peritraumatic dissociation may, in fact, be a proxy risk factor for experiential avoidance. Previously, Kraemer, Stice, Kazdin, Offord, and Kupfer (2001) defined a proxy risk factor as a variable that is highly correlated with a given outcome only through its relationship with another variable that is strongly correlated with that outcome. To date, however, there has been no investigation of the relationships among PTSD symptom severity, peritraumatic dissociation, and experiential avoidance.

The present study examined the notion that peritraumatic dissociation serves as a proxy risk factor for experiential avoidance in its relationship to PTSD symptomatology. In order to demonstrate that peritraumatic dissociation is a proxy risk factor for experiential avoidance in its relationship to PTSD symptomatology, the ability of peritraumatic dissociation to predict PTSD symptomatology levels should diminish when experiential avoidance is taken into account. Additionally, in an attempt to better determine the nature of the relationships among peritraumatic dissociation, experiential avoidance, and PTSD severity, we used a prospective research design with follow-up assessments occurring both 4 and 8 weeks after initial assessment, while controlling for baseline levels of PTSD severity. We chose a prospective design for this investigation because it allowed us to examine the nature of the relationships among PTSD symptoms, peritraumatic dissociation, and experiential avoidance over time, while accounting for baseline PTSD symptom severity. We hypothesized that, at initial assessment, peritraumatic dissociation would serve as a proxy risk factor for experiential avoidance in its relationship with PTSD symptom severity. We also hypothesized that experiential avoidance would continue to predict PTSD symptom severity at both follow-up assessments, even after accounting for baseline levels of PTSD symptomatology.

Section snippets

Recruitment and retention

Participants were drawn from an Introductory Psychology course at a large, urban university. Individuals who reported that they had experienced one or more traumatic stressor(s) were considered potential participants for the study. For the purpose of being consistent with the diagnostic criteria for PTSD (American Psychiatric Association, 2000), a traumatic stressor was defined in this study as a direct personal experience that involved actual or threatened death or serious injury or other

Descriptive analyses

The mean age of the 185 participants who were assessed at baseline was 19.6 (SD=2.6). The majority (i.e., 71%) of these participants were female and White (56%) with the remaining participants representing a diverse racial background (23% African-American, 6% Asian-American, 7% Hispanic, 1% Native American, 1% Pacific Islander, and 6% “other” or mixed racial background). Consistent with the literature (Scarpa, 2001; Scarpa et al., 2002; Vrana & Lauterbach, 1994), a majority of the sample (n=124

Discussion

The present investigation examined whether or not peritraumatic dissociation serves as a proxy risk factor for experiential avoidance in its relationship with PTSD symptomatology among an undergraduate sample of trauma survivors. Using a prospective research design to examine the nature of the relationships among PTSD symptoms, peritraumatic dissociation, and experiential avoidance over time, while accounting for baseline PTSD symptom severity, we found that, at baseline, both peritraumatic

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    A Temple University Research Incentive Fund award and Faculty Summer Fellowship awarded to Brian P. Marx supported this study.

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