Focus Points
• Psychological debriefing does not prevent subsequent psychological disorder.
• Cognitive-behavioral therapy is a promising early intervention after trauma for people who are high risk for posttraumatic stress disorder development.
• D-cycloserine is a promising enhancer of learning that can facilitate cognitive-behavioral therapy.
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ABSTRACT
What are the conceptual and empirical bases for current interventions for acute stress reactions following trauma exposure? This review compares the two major alternatives to managing acute stress reactions, outlines their conceptual bases and critiques the evidence for their efficacy in preventing subsequent stress disorders. The review integrates current evidence for cognitive behavior therapy with recent neuroscience findings that fear reduction learning can be enhanced by modulating glutamaterigc systems. D-cycloserine provides exciting opportunities to enhance the effects of cognitive-behavioral therapy, and points to closer understanding of the biological mechanisms that underpin clinical gains achieved by psychological therapies.
CNS Spectr. 2005;10(2):116-122
Introduction: Psychosocial Approaches of Acute Stress Reactions
Recent events have focused unprecedented attention on the alternative psychosocial approaches to managing acute stress reactions following trauma exposure. This review considers the two most prevalent alternatives available today: psychological debriefing and cognitive-behavioral therapy (CBT). These approaches differ markedly in both their conceptual bases and the degree of supporting evidence. Both approaches currently suffer from a lack of integration between the evidence for their efficacy and evidence for the purported conceptual bases of the respective approaches. It is timely to consider the role of mechanisms that underpin early interventions following trauma because understanding these mechanisms will lead towards more effective interventions of acute stress reactions.
What Are the Mechanisms Underpinning Posttraumatic Stress?
To understand the possible mechanisms of posttraumatic stress, one needs to consider the typical response to trauma. There is overwhelming evidence that the majority of acute stress reactions are transient. For example, whereas 94% of rape victims display sufficient posttraumatic stress disorder (PTSD) symptoms 2-weeks posttrauma to meet criteria (excluding the 1-month time requirement), this rate drops to 47% 11 weeks later.1 Similarly, rates of PTSD reduce by >50% following nonsexual assault2 and motor vehicle accidents.3 Even responses following the terrorist attacks of September 11, 2001, suggest that the normative response was to be resilient following an initial period of distress. Five to 8 weeks after the attacks, 7.5% of a random sample of adults living south of 110th Street in Manhattan had developed PTSD, and of those living south of Canal Street, 20% had PTSD.4 In February 2002, a study5 of adults living south of 110th Street found that only 1.7% of the sample had PTSD related to the attacks.
The tendency for most people to gradually adapt after trauma exposure points to mechanisms that lead some people to a persistent fear response. Evolving from early behaviorist views of classical conditioning,6 many early conceptualizations of traumatic stress were based on conditioning models.7,8 These models posit that exposure to a traumatic event (unconditioned stimulus) leads to a strong fear reaction (unconditioned response), which becomes conditioned to many stimuli associated with the traumatic event. Accordingly, when people are exposed to reminders of the trauma (conditioned stimuli), they experience a strong fear reaction (conditioned response).9 This perspective has observed many similarities between trauma-exposed individuals and animals exposed to threat under experimental conditions. For example, it has been suggested that the conditioned fear response observed in rats who are shocked in the context of a specific stimulus parallels the fear response that PTSD patients experience in relation to the many stimuli associated with the traumatic experience.10 Similarly, many theorists have noted that adaptation to a trauma and successful response to CBT can be understood as extinction learning.11 It is argued that most people adapt to this response with extinction learning in the following period when they learn that the many stimuli initially associated with the trauma experience are now associated with safety, and thereby the initial fear response abates.12 In this sense, persistent stress reactions may be conceptualized as a failure of extinction learning. Repeatedly presenting a previously conditioned fearful stimulus in the absence of the noxious stimulus (with which the stimulus was initially associated) leads to new learning that involves a non-fearful response to the stimulus.13 Importantly, the same neural structures appear to be involved in both fear conditioning and extinction learning.14
Psychological Debriefing
A common approach employed to manage acute stress reactions after exposure to traumatic events is termed psychological debriefing. This approach involves a number of techniques that attempt to reduce posttraumatic stress by intervening in the initial days after trauma exposure.15 Evolving from earlier military practices in which commanders would encourage troops to review combat operations,16 the more recent versions of this approach have been applied to military, emergency service personnel, and civilian populations. The most popular version of debriefing is termed Critical Incident Stress Debriefing (CISD).15 A CISD session often comprises seven phases. In the Introduction Phase, the debriefer explains the session as an opportunity to reduce stress reactions, informs participants that speaking in the group is voluntary, explains that it is not a therapeutic exercise, and answers questions about the session. In the Fact Phase, the debriefer asks participants to describe what they saw and heard during the event. In the Thought Phase, the debriefer inquires about thoughts that occurred during and after the event. In the Reaction Phase, participants are invited to express their emotional responses to the event. In the Symptom Phase, the debriefer asks participants about psychological or physical symptoms in order to ascertain stress reactions experienced by participants. In the Teaching Phase, the debriefer instructs participants about normal stress reactions and suggestions for stress reduction. In the Re-entry Phase, the debriefer summarizes the session, answers questions, makes referral suggestions if warranted. These sessions can last between 3 and 4 hours, and occur between 2–10 days after a critical incident. Although this intervention was initially described as being beneficial for individuals,15 it is typically provided on a group basis and it is provided to all trauma survivors.
The conceptual basis of this approach involves the premise that individuals are vulnerable to developing posttraumatic stress if they are exposed to a traumatic event, and that the single session of debriefing will limit the likelihood of a posttraumatic stress reaction. Proponents of this approach suggest that debriefing can prevent subsequent disorder because it provides psychosocial support, facilitates expression of emotions and thoughts about the trauma, and provides advice on coping strategies.17 The conceptual basis for this approach is fundamentally flawed in terms of providing an intervention to all trauma survivors. The evidence that most people adapt to a traumatic experience after several months challenges the notion that all people require intervention following trauma exposure.
Does Debriefing Prevent Subsequent Disorder?
There are reports that many people who receive debriefing perceive it to be beneficial.18,19 It is important to recognize, however, that perceived help does not equate with efficacy. At this time, there are many studies pertaining to evaluate the utility of debriefing. The majority of these studies20 are poorly conducted and their conclusions are seriously flawed by lack of random allocation to treatment conditions, non-independent assessments, unstandardized measures, and ambiguity about the intervention.16,20 Although proponents of debriefing cite findings that purportedly support the efficacy of debriefing,17,21,22 these studies are inherently flawed by methodological problems.
It needs to be recognized that conducting adequately controlled studies in the aftermath of disaster is difficult because of the chaotic nature of postdisaster settings. Nonetheless, it is imperative that inferences about the efficacy of debriefing are based only on work that has achieved a reasonable degree of methodological rigor. There are studies of debriefing that have imposed some degree of experimental control, including random allocation, assessment before and after the intervention, and independent assessment of post-debriefing functioning.16,20 For example, one study23 randomly assigned survivors of motor vehicle accidents to debriefing or assessment only; the 30-minuite debriefing occurred immediately after the assessment and ~7 days after the accident. Although both groups improved on measures of PTSD symptoms, there were no group differences at 3-month follow-up. Another study randomly assigned 157 adult crime victims to either debriefing, an educational intervention, or assessment only.24 Whereas the individually administered debriefing included discussion of the experience, and direct encouragement to ventilate emotional responses, the education program only involved information about stress reactions. PTSD was identified in 26%, 23%, and 11% in the assessment-only, debriefing, and educational groups, respectively, at the 6-month follow-up. At the 11-month assessment, all groups reported comparably low rates of PTSD.
A study of police officers compared the responses of 46 police officers who received group debriefing after responding to a plane crash with responses of other officers who were unable to attend the debriefing. At 18 months, the groups did not differ on psychopathology measures, apart from the debriefed officers reporting more arousal symptoms than non-debriefed participants. This study is limited by the lack of random allocation and the absence of pre-treatment measures. In an adaptation of debriefing approaches, one study18 administered three CISD sessions to police officers, at 24 hours, 1 month, and 3 months after trauma exposure, and compared responses with two groups of police officers: those who were trauma-exposed before debriefing was introduced and those who refused to participate in debriefing. Although the debriefed officers reported more PTSD symptoms 1-week posttrauma, there were no group differences at the 24-hour and 6-month assessments. This study was also limited by the lack of random allocation.
There is some evidence that debriefing may have toxic effects by impairing the natural recovery that typically occurs following trauma exposure. An earlier study26 assessed earthquake disaster workers who had and had not received debriefing. Responses indicated that the debriefed group reported more symptoms than the non-debriefed group. This finding is limited, however, by the lack of random allocation and some degree of ambiguity about the debriefing practices that were employed. There have been better-controlled studies that have also suggested that debriefing may have negative effects. A study of burn patients randomly assigned patients to either debriefing or an assessment-only control condition.27 Debriefing occurred 2–19 days after the burn. At the 13-month follow-up assessment, the debriefed participants reported more PTSD, anxiety, and depression than non-debriefed participants, even when initial severity of PTSD, anxiety, and depression was controlled for. It should be noted that the debriefed group tended to show more severe injury and distress prior to debriefing than the control participants. It is also questionable whether debriefing was intended to be used for severely burnt individuals because they represent a qualitatively distinct group. A study of motor vehicle accident survivors28 randomly assigned people to either a single individually administered debriefing session that occurred between 24 and 48 hours after the accident or an assessment-only control condition. At the 4-month follow-up, the debriefing participants reported more distress on selected measures than the control participants. It should be noted, however, that the debriefed group appears to have been more severely injured than the control group. Three years later these participants were re-assessed.29 The debriefed participants reported more PTSD symptoms, and functional difficulties than control participants; specifically, participants who initially indicated more severe PTSD reactions and were not debriefed improved markedly. In contrast, participants who initially indicated severe PTSD reactions and were debriefed remained highly symptomatic. Importantly, this finding was not explained by the initially differences in injury severity.
Overall, the available evidence points to debriefing being an ineffective approach in terms of preventing subsequent disorder. Although the evidence that early debriefing may have toxic effects is tentative, it points to the potential problems with interventions that do not assess participants’ suitability before they are included in the intervention. Moreover, several commentators20 have noted that a potential problems with debriefing is that it may exacerbate hyperarousal by requiring participants to disclose their emotional responses in the days after the experience.
Cognitive-Behavioral Therapy
The major alternative to debriefing in the initial phase has been to provide CBT to trauma survivors in the weeks after trauma exposure. The components of CBT include education about trauma responses, anxiety management techniques, cognitive restructuring, and exposure. Education includes learning about the common reactions to a traumatic event, the cognitive and behavioral mechanisms that mediate core PTSD reactions, and a rationale for the treatment. Anxiety management techniques provide individuals with coping skills to reduce arousal, manage fear reactions, and assist management of distressing activities and trauma reminders. Cognitive restructuring is based on models that emphasize the importance of appraisals in the etiology and maintenance of PTSD.30 Cognitive restructuring involves teaching individuals to identify and evaluate the evidence for negative automatic thoughts, as well as helping patients to evaluate their beliefs about the trauma, the self, the world and the future.31 Prolonged imaginal exposure requires the individual to vividly imagine the trauma for prolonged periods. The individual typically provides a narrative of their traumatic experience in a way that emphasizes all relevant details, including sensory cues and affective responses. This exercise usually occurs for at least 50 minutes and is usually supplemented by daily homework exercises. Most exposure treatments supplement imaginal exposure with in vivo exposure that involves graded exposure to the feared trauma-related stimuli.
This approach conceptually differs from debriefing in a number of key domains. First, whereas debriefing aims to prevent disorder in all trauma survivors, CBT focuses on people who are displaying elevated levels of acute stress, and presumably are high risk for subsequent disorder. In this sense, this approach presumes resilience in the majority of people and focus therapy attention only on the minority of people who require assistance. Accordingly, whereas debriefing occurs without any screening or assessment, CBT requires careful clinical assessment. To reduce the likelihood of treating a transient stress reaction and ensuring that people can focus attention on therapy demands, CBT is typically commenced several weeks after trauma exposure.
Second, in contrast to the single session of group debriefing, CBT is provided over a series of individual sessions that typically require considerable homework exercises between sessions. Third, CBT is based on the concept that acute stress is mediated by a number of related responses. Acute stress is characterized by elevated arousal and fear that is established by strong fear conditioning in the immediate aftermath of the traumatic experience.32 Recogizing that elevated hyperarousal, conditioned fear, and the presence of maladaptive appraisals contribute to posttraumatic stress, CBT approaches adopt an explicit strategy of targeting these mechanisms through anxiety management, cognitive therapy, and exposure paradigms.33 It appears that these various techniques can beneficially influence a range of posttraumatic stress symptoms. For example, exposure can reduce maladaptive appraisals34
and cognitive therapy can reduce anxiety and avoidance.35
An initial study of CBT36 provided brief CBT to sexual and nonsexual assault victims shortly after the assault. This study compared four sessions CBT, (including exposure, anxiety management, in vivo exposure, and cognitive restructuring) with matched participants who had received repeated assessments. Whereas 10% of the CBT group met criteria for PTSD at 2 months, 70% of the control group met criteria; there were no differences between groups at 5 months, although the CBT group was less depressed. A subsequent study (E.B. Foa oral communication, November 2002) by the same team randomly allocated survivors of assault who met criteria for PTSD in the initial weeks after the assault to four weekly sessions of CBT, repeated assessment, or supportive counseling (SC). SC was associated with greater PTSD severity and greater general anxiety than the CBT group.
Another approach has tried to focus on individuals who are particularly high risk for PTSD to limit the likelihood that any symptom reduction is not a function of natural remission. To this end, several studies have focused on people who display acute stress disorder (ASD) in the initial month after trauma exposure. Across a range of studies, ~75% of people who display ASD in the initial month after trauma exposure still meet PTSD criteria 6 months later.37 Focusing on people with ASD may provide a stricter test of the efficacy of early interventions because there is less chance that natural remission will contribute to symptom reduction.
An initial study of ASD participants randomly allocated motor vehicle accident or nonsexual assault survivors with ASD to either CBT or SC.38 Both interventions consisted of five 1.5-hour weekly individual therapy sessions. CBT included education about posttraumatic reactions, relaxation training, cognitive restructuring, and imaginal and in vivo exposure to the traumatic event. SC condition included trauma education and more general problem-solving skills training in the context of an unconditionally supportive relationship. At the 6-month follow-up, there were fewer participants in the CBT group (20%) who met diagnostic criteria for PTSD compared with SC control participants (67%). A subsequent study by the same team randomly allocated 45 civilian trauma survivors with ASD to five sessions of either CBT (prolonged exposure, cognitive therapy, anxiety management); prolonged exposure combined with cognitive therapy; or supportive counseling.39 This study found that at 6-month follow-up, PTSD was observed in ~20% of both active treatment groups compared with 67% of those receiving SC. Follow-up of participants who completed these two treatment studies indicated that the treatment gains of those who received CBT were maintained 4 years after treatment.40 Another study41 randomly allocated 89 civilian trauma survivors with ASD to either CBT, CBT associated with hypnosis, or SC. This study added hypnosis to CBT because some commentators have argued that hypnosis may breach dissociative symptoms that characterize ASD.42 The hypnosis component was provided immediately prior to imaginal exposure in an attempt to facilitate emotional processing of the trauma memories. In terms of treatment completers, more participants in the SC condition (57%) met PTSD criteria at 6-month follow-up than those in the CBT (21%) or CBT plus hypnosis (22%) condition. Finally, a recent study was conducted on a sample of ASD participants who sustained mild traumatic brain injury following MVAs.43 This study investigated the efficacy of CBT in people who lost consciousness during the trauma as result of their traumatic injury. Consistent with the previous studies, fewer participants receiving CBT (8%) met criteria for PTSD at 6-months follow-up than those receiving SC (58%).
Using a different approach, another study44 provided a two-session CBT intervention that was intended to promote memory reconstruction in 17 survivors of accidents. Using an entry criterion of a heart rate >94 beats/minute at admission to the emergency room,45,46 this study provided a telephone-administered protocol 1–3 days after the accident. Patients who received this intervention had greater reductions in severity of PTSD symptoms 3–4 months after the trauma than did those who received two sessions of supportive listening over the telephone.
Enhancing Cognitive-Behavioral Therapy
Although the initial evidence points to promising benefits form early provision of CBT, the current evidence also suggests some major limitations to this approach. A significant proportion of participants drop out of treatment. For example, 20% of participants dropped out of two of the studies conducted on people with ASD.39,41 Accordingly, intent-to-treat analyses in these studies are not so promising for the benefits of early CBT. Additionally, there are reports that a proportion of people are not able to tolerate CBT in the initial weeks after trauma exposure and may experience an exacerbation of symptoms.47 These observations underscore the need to recognize that in the initial weeks after trauma exposure, the fragile presentation of some people may render them vulnerable to adverse effects of treatment.
On the premise that fear reduction is a learnt response, commentators have proposed that extinction learning may be enhanced by modulating neurotransmitters that mediate learning.11 Expanding on the earlier behavioral and cognitive therapies of posttraumatic stress,8,48 there is interest in enhancing the benefits of CBT through targeting the neural systems that mediate learning. There is considerable evidence that glutamate plays an important role in learning and memory.49 Extending this notion to the study of fear, earlier evidence indicated that infusions of N-methyl-d-aspartate (NMDA) receptor antagonists impaired fear conditioning.50 Researchers subsequently began investigating the possibility that modulating NMDA receptors in the amygdala may influence extinction learning.51 Subsequent findings11 indicated that NMDA receptors in the amygdala were important in fear extinction. In more recent years, attention has focused on the possibility of enhancing extinction learning by employing NMDA agonists. Specifically, D-cycloserine (DCS), which is a partial agonist at the NMDA glutamatergic receptor, has been shown to facilitate learning in animal52 and human53 studies. DCS is particularly useful in the context of applying it to human learning because it is used in treatment of tuberculosis and clinically effective doses are not associated with adverse sid effects. The utility of DCS has been indicated by repeated demonstrations that administration of DCS prior to extinction learning in rats facilitates reduction of the fear response.49,54 An exciting possibility that modulating glutamatergic activity may enhance extinction learning in posttraumatic stress is indicated by initial findings that administration of DCS prior to exposure therapy for height phobia results in greater anxiety reduction relative to placebo administration.55 The potential application of DCS to treating posttraumatic stress is underscored by recent evidence that DCS also reduces reinstatement of fear when rats are exposed to the unconditioned stimulus after extinction training.56 Considering the prevalence of relapse and the elevated risk of further anxiety when trauma-exposed people are subsequently re-exposed to stressors, DCS may enhance the longer-term benefits of CBT.
Future Directions
The opportunity to identify the neurobiological mechanisms associated with extinction learning, and to modify learning through direct modulation of the relevant systems, opens up new opportunities for enhancing the therapeutic benefits of CBT. Considering that CBT evolved from seminal studies conducted on animals in feared situations, it is hardly surprising that advances made in animal neuroscience may shape future directions in applying CBT to posttraumatic stress. This translational approach to understanding and managing posttraumatic stress that integrates animal and human responses to fear has the potential to advance both our theoretical models of posttraumatic stress and the potency of our treatment methods.
Conclusion
Our knowledge about acute stress reactions and the ways to manage them has grown significantly in recent years. In contrast to the previous approach that assumed that all trauma survivors were vulnerable and required formal assistance, we have now developed a more empirically informed response to trauma. Most importantly, there is increasing recognition that acute trauma response needs to integrate the findings of sound basic and clinical research.
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Dr. Bryant is professor of psychology in the School of Psychology at the University of New South Wales in Sydney in Australia.
Disclosure: This review was supported by a National Health and Medical Research Council Program Grant (300304). The author does not have any affiliations with or financial interest in any organization that might pose a conflict of interest. This article was submitted on March 8, 2004, and accepted on November 1, 2004.
Please direct all correspondence to: Richard A. Bryant, PhD, School of Psychology, University of New South Wales, NSW, 2052, Australia; Tel: 61-2-9385-3640, Fax: 61-2-9385-3641; Email: r.bryant@unsw.edu.au.