Elsevier

Journal of Affective Disorders

Volume 217, 1 August 2017, Pages 246-251
Journal of Affective Disorders

Research paper
Negative appraisals and fear extinction are independently related to PTSD symptoms

https://doi.org/10.1016/j.jad.2017.04.016Get rights and content

Highlights

  • PTSD is associated with slower fear extinction learning.

  • PTSD is associated with negative appraisals of a trauma.

  • Negative appraisals are not a moderator of fear extinction and PTSD.

  • Fear extinction and negative appraisals play separate roles in PTSD.

Abstract

Background

Considerable research has revealed impaired fear extinction to be a significant predictor of PTSD. Fear extinction is also considered the primary mechanism of exposure therapy, and a critical factor in PTSD recovery. The cognitive theory of PTSD proposes that symptoms persist due to excessive negative appraisals about the trauma and its sequelae. Research has not yet examined the relationship between fear extinction and negative appraisals in PTSD.

Methods

A cross-sectional sample of participants with PTSD (n =21), and trauma-exposed controls (n =33) underwent a standardized differential fear conditioning and extinction paradigm, with skin conductance response (SCR) amplitude serving as the index of conditioned responses. The Posttraumatic Cognitions Inventory (PTCI) was used to index catastrophic negative appraisals.

Results

Participants with PTSD demonstrated a slower decrease in overall SCR responses during extinction and greater negative appraisals compared to the group. A moderation analysis revealed that both negative trauma-relevant appraisals and fear extinction learning were independently associated with PTSD symptoms, but there was no moderation interaction.

Limitations

The current study was limited by a modest sample size, leading to the inclusion of participants with subclinical PTSD symptoms. Further, the current study only assessed fear extinction learning; including a second day extinction recall task may show alternative effects.

Conclusions

These findings indicate that negative appraisals and fear extinction did not interact, but had independent relationships with PTSD symptoms. Here we show for the first time in an experimental framework that negative appraisals and fear extinction play separate roles in PTSD symptoms.

Introduction

Posttraumatic Stress Disorder (PTSD) is characterized by persistent fear, intrusive memories, and negative appraisals about oneself and a traumatic event (Dunmore et al., 1999). Symptoms naturally subside in many trauma survivors, but persist as PTSD in approximately 2–10% of people (Atwoli et al., 2015, Ramchand et al., 2010). The cognitive theory of PTSD (Ehlers and Clark, 2000) proposes that two key mechanisms underlie the persistence of PTSD: negative appraisals relating to the trauma and its sequelae, and poorly elaborated autobiographical memories and conditioned fear responses which readily prime intrusive memories that are triggered by trauma reminders (Ehlers and Clark, 2000).

A considerable body of research supports the idea that PTSD develops and is maintained by negative cognitions about a significant traumatic event (Dunmore et al., 1999, Dunmore et al., 2001, Ehlers et al., 1998, Ehlers et al., 2003). That is, traumatic experiences lead to negative appraisals about the trauma and its sequelae, causing feelings of current threat, persistent avoidance, and generalization of fear (Ehlers and Clark, 2000). Numerous studies have shown that acute post-trauma negative appraisals significantly predict increased PTSD symptoms in adults and children following a range of traumatic events (e.g., Dunmore et al., 2001; Ehlers et al., 1998, Ehlers et al., 2003; Ehring et al., 2008). Moreover, the tendency to engage in negative appraisals prior to a traumatic event predicts PTSD symptoms several years after exposure (Bryant and Guthrie, 2007).

A second influential model proposes that PTSD develops from impaired fear extinction learning and recall (Pitman et al., 2012). In this model, fear conditioning occurs during trauma, and re-exposure to trauma reminders and subsequent avoidance of reminders facilitate conditioned fear and fear generalization. Extinction typically occurs when the conditioned stimuli are presented in the absence of any aversive consequence, and in the context of trauma this typically involves experience of benign trauma reminders. In this sense, the minority of trauma survivors who experience persistent symptoms can be regarded as suffering impaired extinction (Davis and Myers, 2002). Considerable evidence demonstrates that individuals presenting with PTSD show impairments in fear extinction and extinction recall (e.g., Milad et al., 2008; Norrholm et al., 2011; Shvil et al., 2014; Zuj et al., 2016a). Recent studies have also found pre-trauma extinction learning significantly predicts increased post-traumatic stress (Guthrie and Bryant, 2006, Lommen et al., 2013, Orr et al., 2012). Further, psychophysiological indices of conditioned fear (e.g., fear-potentiated startle and skin conductance response) have been suggested as intermediate phenotypes and central factors of trauma- and stressor-related disorders (Briscione et al., 2014, Zuj et al., 2016b).

These models are not mutually exclusive, given that Ehlers and Clark (2000) also suggest that intrusive memories and conditioned fear responses triggered by trauma reminders are thought to reinforce negative appraisals, which act to maintain anxiety and sense of current threat. Further, longitudinal evidence has found that PTSD symptoms can be predicted by pre-trauma fear extinction learning (Guthrie and Bryant, 2006), and maladaptive pre-trauma negative appraisals (Bryant and Guthrie, 2007). Therefore, pre-trauma impaired extinction capacity and heightened negative appraisals may interact to potentiate fear responses following trauma. In an experimental framework, negative appraisals may moderate the relationship between fear extinction and PTSD symptoms. To our knowledge, no previous studies have examined fear extinction and negative appraisals in tandem, in relation to PTSD.

In the present study, we were interested in understanding the extent to which fear extinction learning and negative appraisals are uniquely and interactively related to PTSD symptom severity. On the basis of Ehlers and Clark's (2000) model, we predicted first that excessively negative appraisals (indexed by the Posttraumatic Cognitions Inventory (PTCI)) would be associated with increased PTSD symptom severity. Second, on the basis of considerable cross-sectional and longitudinal evidence we hypothesized that impaired fear extinction learning would be associated with PTSD symptoms. As yet, studies have not considered these two prevailing models in tandem, thus moderation analyses were conducted to test for a possible interaction between fear extinction learning and negative appraisals in influencing PTSD symptom severity.

Section snippets

Participants

Fifty-four participants aged 18–63 years (M =29.5 years, SD =12.2 years; 26 males and 28 females) comprised two groups: PTSD (n =21) and trauma-exposed without PTSD (TC; n =33). The PTSD and TC groups were classified on the basis of experiencing a criterion A stressor, whereby physical integrity was threatened (American Psychiatric Association, 2000, American Psychiatric Association, 2013) using the Traumatic Events Questionnaire (TEQ; Vrana and Lauterbach, 1994). Traumatic events included

Descriptives and clinical data

One-way ANOVA showed that there was a significant between-group difference in PCL-C total symptom severity, F(1, 23.15) =127.68, p<.001, with the PTSD group displaying significantly elevated PTSD symptoms compared to the TC group. Further, the PTSD group displayed significantly higher levels of negative appraisals, and symptoms of depression, anxiety, and stress than the TC group (see Table 1 for demographic and inferential data). There were no significant group differences on age or alcohol

Discussion

The results of the present study suggest that both negative appraisals and fear extinction learning are associated with elevated PTSD symptoms. This study was the first to our knowledge to examine whether negative appraisals and fear extinction learning interact to influence PTSD symptoms. Moderation analyses revealed that negative appraisals did not moderate the relationship between fear extinction and PTSD symptoms, suggesting that fear extinction and negative appraisals do not interact in

Role of the funding source

This project was supported by an NHMRC Project grant (APP1050848) and an NHMRC Program grant (APP1073041). Daniel Zuj was supported by an Australian Postgraduate Award from the Australian Government for the duration of this research.

Acknowledgements

We wish to thank Pippa Cushing, Amy Swindon, and Latifa Clark-Walters for assistance with data collection.

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