Building child trauma theory from longitudinal studies: A meta-analysis

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Abstract

Many children are exposed to traumatic events, with potentially serious psychological and developmental consequences. Therefore, understanding development of long-term posttraumatic stress in children is essential. We aimed to contribute to child trauma theory by focusing on theory use and theory validation in longitudinal studies. Forty studies measuring short-term predictors and long-term posttraumatic stress symptoms were identified and coded for theoretical grounding, sample characteristics, and correlational effect sizes. Explicit theoretical frameworks were present in a minority of the studies. Important predictors of long-term posttraumatic stress were symptoms of acute and short-term posttraumatic stress, depression, anxiety, and parental posttraumatic stress. Female gender, injury severity, duration of hospitalization, and elevated heart rate shortly after hospitalization yielded small effect sizes. Age, minority status, and socioeconomic status were not significantly related to long-term posttraumatic stress reactions. Since many other variables were not studied frequently enough to compute effect sizes, existing theoretical frameworks could only be partially confirmed or falsified. Child trauma theory-building can be facilitated by development of encouraging journal policies, the use of comparable methods, and more intense collaboration.

Research highlights

► A minority of longitudinal child trauma studies is explicitly based on theory. ► General risk factor, biological, and cognitive models are used most often. ► Acute, short-term, and parental distress moderately to strongly predict long-term child posttraumatic stress while gender, injury severity, duration of hospitalization, and acute heart rate are weak predictors. ► Age, minority status, and SES do not predict long-term child posttraumatic stress. ► Child trauma theory-building can be facilitated in several ways.

Introduction

When children are confronted with trauma, caregivers and professionals search for ways to prevent or reduce long-term distress. Many children are exposed to traumatic events and their psychological and developmental consequences can be serious (Fairbank & Fairbank, 2009). As the occurrence of severe distress after trauma appears to be a non-random phenomenon (Ozer, Best, Lipsey, & Weiss, 2003), solid knowledge of risk factors, protective factors and the mechanisms by which they influence posttraumatic stress in children is needed. The purpose of this paper is to contribute to this knowledge base by focusing on theory use and theory validation in a meta-analytic approach.

Traumatic exposure involves a confrontation with actual or threatened death, serious injury, or other threat to physical integrity (American Psychiatric Association, 2000). Examples include natural disasters, serious accidents, (mass) violence, and sudden loss of a loved one. Trauma exposure is fairly prevalent in children. Peacetime general population studies reported rates of exposure to any traumatic event from 14% (Alisic, Van der Schoot, Van Ginkel, & Kleber, 2008) to more than 65% (Copeland et al., 2007, Elklit, 2002). In addition, in a number of countries large populations, including children, are subjected to war (Ehntholt & Yule, 2006). Although it was previously thought that trauma caused only transient distress in children, it is now generally accepted that it can cause severe and long-term impairment (Yule, 2001). The most studied psychological consequences of traumatic exposure in children are posttraumatic stress and its pathological extremity, posttraumatic stress disorder (PTSD; American Psychiatric Association, 2000).

PTSD is characterized by overwhelming feelings of reexperiencing the traumatic event (e.g., nightmares and intrusive thoughts), by the avoidance of stimuli and emotional numbing (e.g., avoiding places related to the event and feeling detached from others), and by symptoms of hyperarousal (e.g., concentration difficulties and hypervigilance; American Psychiatric Association, 2000). As was posited in the 1980s by Terr (1983) and confirmed many times since then, posttraumatic stress occurs not only in adults but also in children. Children can suffer from PTSD for many years (Yule et al., 2000) which affects their well-being and development in emotional, social, academic, as well as physical domains (Fairbank and Fairbank, 2009, Pynoos et al., 2009, Seng et al., 2005, Yule, 2001).

Fortunately, most children who have been exposed to trauma do not develop PTSD. Estimations vary widely, but in a synthesis of 34 studies, 64% of the children who were exposed to trauma did not develop PTSD (Fletcher, 2003). Nevertheless, about one in three children did, and several researchers suggest that subclinical levels of PTSD also cause severe impairment and distress (Carrion, Weems, Ray, & Reiss, 2002). Understanding the mechanisms underlying the considerable individual variability in psychological responses to trauma (Ozer et al., 2003) is valuable both for the identification of children at risk for long-term distress and for the development of effective treatment programs. Which factors cause severe distress and which factors are levers that can be used to reduce symptoms and successfully strengthen children?

Although several theories have been proposed to explain the development of PTSD in adults (for an overview, see Brewin & Holmes, 2003) these cannot readily be applied to children. Children are thought to respond to traumatic events in a somewhat different way from how adults react (see ⁎Kenardy et al., 2007, Salmon and Bryant, 2002). For example, children have a more limited knowledge base than adults. This may result in the failure to appraise an experience accurately, potentially influencing the memory of the experience and children's emotional response to it (Salmon & Bryant, 2002), in a different way than it would influence adults. Also, children's ability to use various coping strategies to regulate emotion is likely to be influenced by their advances in development, such as their understanding of emotion (Gross and Thompson, 2007, Salmon and Bryant, 2002). In addition, young children appear to rely heavily on how their parents deal with stress (see Scheeringa & Zeanah, 2001). Therefore, their adjustment to trauma is influenced differently by their environment than an adults' adjustment.

Although compared with adults little theory has been developed to understand childhood posttraumatic stress (Salmon & Bryant, 2002), a number of conceptualizations have emerged. For example, La Greca, Silverman, Vernberg and Prinstein (1996) modeled responses to natural disaster. They identified exposure characteristics (e.g., life threat during the event and loss or disruption following the event), pre-existing child characteristics (e.g., gender, ethnicity, age), the post-disaster recovery environment (e.g., major life events, social support) and the coping skills of the child as important factors influencing children's posttraumatic reactions. Pynoos, Steinberg, and Piacentini (1999) described a model that distinguishes between children's acute distress and longer-term adjustment after traumatic exposure. Short-term reactions are thought to be related to the experience of the trauma and influenced by a) proximal trauma reminders (e.g., media coverage), b) proximal secondary stresses (e.g., loss of resources), c) the ecology of the child (e.g., parental psychopathology), and d) child intrinsic factors (e.g., temperament). Children's ongoing adjustment is further related to e) ongoing reminders of the trauma, f) persistent secondary stressors, and g) related or sequential traumatization.

While the two models outlined above provide overviews of factors influencing posttraumatic stress in children, several authors have zoomed in on specific mechanisms. For example, Ehlers and colleagues (Ehlers, Mayou, & Bryant, 2003) focused on cognitive processes and suggested that the Ehlers and Clark (2000) model fits children. This model highlights the role of a) trauma memory deficits due to incomplete cognitive processing during the event and cognitive avoidance after the event, b) excessively negative appraisals of the event leading to a sense of current threat, and c) dysfunctional behaviors and cognitive strategies that are intended to control the perceived current threat but maintain the problem (e.g., thought suppression). Another illustration concerns child coping theory. While earlier coping theories dichotomized coping into a problem-focused approach, or primary coping on the one hand, and emotion-focused, avoidant, or secondary coping on the other hand (see Compas, Connor-Smith, Saltzman, Thomsen, & Wadsworth, 2001 for an overview), current theory assumes three or more clusters of strategies that are important in dealing with stress. For example, Ayers, Sandler, West, and Roosa (1996) distinguished problem-focused, direct emotion-focused, distraction, avoidance, and support-seeking strategies. Researchers expect certain strategies to be more effective than others, depending on time point and context (Zehnder, Prchal, Vollrath, & Landolt, 2006). A final example of specific theories regards social processes. Scheeringa and Zeanah (2001) have focused on parent–child interactions after trauma. They developed a theory of “relational PTSD” and identified three dysfunctional interaction patterns between parents and young children after traumatic exposure that exacerbate children's symptoms (i.e., withdrawn, overprotective, and frightening patterns).

Several areas of trauma-focused theory that have been developed for adults, such as biological theories and theories invoking multiple representation structures (see Brewin & Holmes, 2003), have not yet seen clear equivalents for children. Other, child-focused areas, such as those regarding social ecology (Bronfenbrenner, 1986), emotion regulation (Gross & Thompson, 2007), and cognitive development (see Miller, 2002 for an overview) have been developed for children in general but are rarely applied to the area of child traumatic stress.

In order to further child trauma theory and understand which factors influence posttraumatic stress and recovery, it is necessary to test current theories and build on them. Explicit theory building is an efficient method for field development in this regard (Wacker, 1998). When researchers explicitly describe the theoretical background of their work in the reports of their findings, this accelerates knowledge growth. Readers easily understand which theory is tested and which parts of it do or do not “pass the test.” This stimulates focused new research that adds to these tests or develops alternatives. Therefore, for the development of a field, using theory explicitly to guide research efforts is more efficient than using it implicitly. The number of empirical studies in children who have been exposed to trauma is growing rapidly, which facilitates the task of testing current theories by synthesizing evidence.

Two meta-analyses have examined predictors of posttraumatic stress in children to date (Cox et al., 2008, Kahana et al., 2006). Kahana et al. (2006) looked into 26 studies in young people who had experienced accidental injuries (18 studies) or illness (8 studies). They found large to very large effect sizes for internalizing symptoms, depressive symptoms, symptoms of anxiety, dissociation, and acute stress disorder; small effects for socioeconomic status, social impairment and social support; and mixed results for age, gender, appraisal of trauma or illness severity, and life threat. Cox et al. (2008) examined 14 articles on accidental injury in children (eight of which were also included in the analysis by Kahana et al.). The strongest and most robust predictive factors accounted only for small to moderate effects. These factors were pretrauma psychopathology, female gender, life threat, and posttrauma parental distress.

These meta-analyses differ in their conclusions, implying that more research is necessary. They also have several limitations. First, they combined cross-sectional and longitudinal data. Cross-sectional estimates may provide misleading figures. For example, the appraisal of life threat may cause heightened posttraumatic stress scores but it is also possible that those children with higher stress scores are simply more prone to remembering life threat than children with lower stress scores. A second concern regards the meta-analysis performed by Kahana et al. which combined several effect sizes based on only two or three studies. Although it is true that two studies is the minimum for an average to be computed, these averages are heavily influenced by the few number of studies included, and they may be rather specific to these studies. Combined with the cross-sectional design, this may lead to over- or underestimation of effect sizes. Third, the findings of these meta-analyses are specific to the types of trauma studied (accidental injury and illness) and the research setting (hospital). Theory validation would profit from being tested across different types of trauma and different settings (cf. Layne et al., 2009).

The purpose of this paper is to contribute to child trauma theory building by focusing on theory use and theory validation. For this purpose we have synthesized reports on longitudinal studies looking at recovery in children after a wide range of traumatic events. Our research questions were:

  • a)

    To what extent has longitudinal child trauma research been based on theoretical frameworks, and which theories are these?

  • b)

    To what extent have risk and protective factors in longitudinal studies been found to predict posttraumatic stress symptoms in children?

The answers will provide information on the validity of current theories, in whole or in part, and on gaps that should be addressed in future research.

Section snippets

Retrieval and selection of studies

We targeted longitudinal studies depicting a natural process of recovery after trauma in children in order to shed light on relevant risk and protective factors. We defined this natural process as a situation in which some children and families will seek help and others will not, as happens in “normal” circumstances after trauma (samples should not be non-treatment seeking per se, but those studies that included the provision of an intervention were not selected; cf. Tolin & Foa, 2006).

Results

We retrieved 68 articles describing 40 independent studies (see also Table 1 of the online supplement). Four studies had been included by both Kahana et al., 2006, Cox et al., 2008, while seven were selected by one of them. We included 29 studies that had not been examined by Kahana et al. or Cox et al. Although we searched from 1980 onward, selected studies were published for the first time between 1992 and 2009, with modest peaks in 2003, 2006, and 2007 (five studies each). Most studies

Discussion

The purpose of this paper is to contribute to child trauma theory building by focusing on theory use in longitudinal studies and on theory validation based on the findings of these studies. We retrieved 40 studies published in the last 30 years that examined predictors (within three months posttrauma) of long-term posttraumatic stress (at three or more months posttrauma) in children. We summarized their use of theory, study characteristics, and the correlational effect sizes for 12 predictors.

Acknowledgements

We thank Drs. Bronner, Dyb, Delahanty, El-Sarraj, Garralda, Gledhill, Karabekiroglu, Kenardy, Kim, La Greca, Le Brocque, Marian, Meiser-Stedman, Miller, Ostrowski, Pervanidou, Pina, Punamäki, Rohrbach, Saxe, Schäfer, Tate, Villalta, Wang, Weems, Zatzick, and Zink Hass for providing additional information on the studies included in the review. We thank Roos Huijbregts, Petra Klaassen, Gerty Lensvelt-Mulders, Renske Schappin, Mirjam Schippers, and Karina van de Voorde for their help in the coding

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    This study was supported by grants from two Dutch foundations: Stichting Achmea Slachtoffer en Samenleving and Fonds Slachtofferhulp.

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