traumatic event is a critical factor in stress reactions

traumatic event is a critical factor in stress reactions,PTSD(American Psychiatric Association,2000)is typically observed in only 5–10% of exposed or exceptionally aversive events,the proportion of full–down PTSD reactions may reach higher levels,sometimes as high as one–third of the sample.This was evident in a study of 2752 individuals drawn by probability sampling from the New York metropolitan area during the weeks and months following the 9/11 terrorist attacks.Overall,the prevalence of PTSD for this sample was estimated at 6%(Bonanno,Galea,Bucciarelli,& Vlahov,2006).However,among those physically injured in the attacks,PTSD prevalence rose to 26%.In another study reanalyzing the National Vietnam Veterans Readjustment date, a representative sample of 1200 veterans,chronic PTSD was estimated at 9% overall,but among veterans with the highest levels of combat exposure the estimate was 28%(Dohrenwend et al.,2006).In studies of bereavement,the proportion of persons who display more severe and chronic reaction to loss is similar.Although estimates vary somewhat,it is typically thought that 10-15% of bereaved people Will develop chronically elevated grief reaction(Bonanno & Kaltman,2001).As was the case for potentially traumatic events in general,however,chronic grief reactions tend to be more prevalent following more extreme losses,such as loss from a violent cause（Kaltman & Bonanno,2003;Zisook,Chentsova-Dutton, & Shuchter,1998）or when the lost loved one was a child(Bonanno, Papa, Lalande,Zhang,&Noll,2005).Delayed ReactionsWhat about delayed reactions?A long-held assumption in the bereavement literature is that the absence of overt signs of grieving,by virtue of its assumed link with denial,will eventually manifest in delayed grief reactions(Bowlby,1980a;Deutsch,1937; Osterweis et al.,1984;Parkes & Weiss,1980;Rando,1993;Sanders,1993).Despite the strength of this belief,however,empirical evidence for delayed grief has never been reported(Bonanno & Kaltman,1999;Wortman & Sliver,1989),even in longitudinal studies explicitly designed to measure the phenomenon(Bonanno & Field,2001;Middleton,Burnett,Raphael,& Martinek,1996).By contrast,there is some evidence for delayed PTSD reactions following potentially traumatic events,occurring in approximately 5-10%of exposed individuals(Bonanno,Rennicke,& Dekel,2005;Buckley,Blanchard,& Hickling,1996).It is crucial to note,however,that this pattern dose not conform to the traditional idea of denial manifesting in delayed reactions.Rather,exposed individuals who eventually manifest delayed PTSD tend to have had relatively high levels of symptoms in the aftermath of the stressor event (Bonanno,Rennicke,et al.,2005;Buckley et al.,1996).thus,the delayed pattern is more appropriately conceptualized as subthresholdpsychopathology that gradually grew worse over time(Bonanno,2004;Buckley et al.,1996).Recovery and ResilienceUntil recently,it was widely assumed that the enduring absence of trauma symptoms following exposure to a potentially traumatic event was rare and would occur only in people with exceptional emotional strength(Casella & Motta,1990;McFarlane&Yehuda,1996; Tucker et al.,2002).And,as noted earlier,bereavement theorists have persistently regarded the relative absence of grief as a form of denial or hidden psychopathology (Middleton et al.,1993).There is now compelling evidence,however,that a genuine and enduring Resilience is not rare but is common and neither a sign of exceptional strength or psychopathology,but a fundamental feature of normal coping skills(Bonanno,2004).Moreover,there is growing evidence that resilience and recovery can be mapped as discrete and empirically separable outcome trajectories.Distinctions between resilience and recovery have been identified,for example,following loss (Bonanno et al.,2005).We consider these distinctions in more detail below.Development of the Construct of Psychological Resilience Much of the original theorizing on resilience came from developmental psychologists and psychiatrists during the 1970s.These pioneering researchers documented the large number of children who despite growing up in caustic socioeconomic circumstances(e.g., poverty)nonetheless evidenced healthy developmental trajectories (Garmezy,1991;Murphy & Moriarty,1976;Rutter,1979;Werner,1995).A surprising feature was that this work showed resilience in at-risk children to becommon(Masten,2001).Where as traditional deficit-focused models of development had assumed that only children with remarkable coping ability could thrive in such adverse contexts,a growing body of evidence began to suggest that resilience is a result of normal human adaptational mechanisms (Masten,2001).As noted earlier,however,most of this research focused on enduring aversive contexts rather than isolated,potentially traumatic events.Although,at the time of these studies,the construct of resilience had not yet "trickled up"to the adult literature,there were sporadic sports of widespread resilience among adults exposed to isolated,potentially traumatic events (Bonanno,2004;Rachman,1978).More recently,however,as the resilience construct has gained currency among trauma researchers,the differences between resilience outcomes in adults and children have become apparent(Bonanno,2004,2005;Bonanno & Mancini,2008),some of the key differences seem to hinge on the temporal and sociocontextual characteristics of stress and adaptation at different points in the lifespan.For development children,the definition of healthy adaptation is a complex issue（Luther,Cicchetti,& Becker,2000;Masten,2001）.For example,children at risk may evidence competence in one domain but fail to meet long-term developmental challenges in other domains (Luther,Doernberger,& Zigler,1993).By contrast,for adults exposed to a potentially traumatic event,this situation is arguably more straightforward(Bonanno ,2004,2005).Most,but certainly not all,of the potentially traumatic events that adults may confront can be classified as isolated stressor events(e.g.,an automobile accident )that occur in a broader context of otherwise normative (i.e.,lowsstress )circumstances.Concomitant stressors may accompany or extend the potentially traumatic event（e.g., enduring problems or change in financial situation),but this level of variability is usually straightforward and can be measured with a reasonable degree of reliability (Bonanno et al.,2006;Bonanno,Moskowitz,Papa,&Folkman,2005).Finally,because development considerations are less pronounced in adults,responses to potentially traumatic events can usually be assessed in terms of deviation from or return tonormative(baseline)functioning (Carver,1998).Based on these considerations,Bonanno(2004)defined resilience as “the ability of adults in otherwise normal circumstances who are exposed to an isolated and potentially highly disruptive event such as the death of a close relation or a violent or lifethreatening situation to maintain relatively stable,healthy levels of psychological and physical functioning ...as well as the capacity for generative experiences and positive emotion”(pp.20-21).this definition contrasts resilience with a more traditional recovery pathway characterized by readily observable elevations in psychological symptoms that endure for at least months before gradually returning to baseline,pretrauma levels.a key point is that even resilient individuals may experience at least some form of transient stress reaction.However,these reactions are usually mild to moderate in degree,relatively short term,and do not significantly interfere with their ability to continue functioning(Bisconti,Moskowitz,et al.,2005;Bonano et al.,2002;Ong,Bergeman,Bisconti,&Wallace,2006).For example,resilient individuals may have difficulty sleeping,or experience intrusive thoughts or memories of the event for several days or even weeks,but most can still manage to perform adequately the tasks of their daily life ot career,or care for others.This is not to say,of course,that people showing resilient outcomes were not upset,disturbed,or unhappy about the occurrence of the event.Our point is merely that as undesirable as potentially traumatic events might be,many people cope with such events extremely well and are able to continue meeting the normal daily demands of their lives.Until recently,most of the evidence that might support such a definition of resilience has been indirect .The earliest observations of. resilience in response to an isolated but potentially devastating stressor event came from retrospective and unsystematic accounts (Janis,1951;Rachman,1978).More recently,a number of studies have demonstrated widespread resilience among people confronted with the untimely death of a spouse or child(Bonanno,Moskowitz,et al.,2005;Bonannoet al.,2002).Although these studies used a variety of different measures of adaptation,a resilient trajectory was consistently observed in about half the bereaved participants.Several studies have also demonstrated widespread resilience among survivors of the 9/11 terrorist attacks in New York City.In one study using a sample of people in or near the World Trade Center at the time of theattacks,resilient individuals showed little or no symptoms of PTSD or depression and were also described as resilient in anonymous ratings made by their close friends and relatives (Bonanno,Rennicke,et al.,2005).Another more encompassing study examined the prevalence of resilient outcomes using date from a large probability sample (N=2752)that closely matched more recent New York census date (Bonanno et al.,2006).Of particular importance,because the sample varied in both geographic location and experiences during and after the attacks,it was possible to compare directly the prevalence of resilient outcomes across different levels of potential trauma exposure.Resilience in this study was defined as one or zero PTSD symptoms during the first 6 mouths after the attacks,and an absence of depression and substance use.Consistent with previous studies,across most exposure groups,the proportion with resilient outcomes was at or above 50% of the sample.Even among the groups with the most pernicious levels of exposure and highest probable PTSD,the proportion that was resilient never dropped below one-third of the sample.Similar findings have also began to emerge following serious health-related stressors.Deshields and colleagues (2006)mapped the same outcome trajectories depicted in Figure 13.1using depression scores obtained from woman immediately following radiation treatment for breast cancer ,and again 3 and 6 months after treatment.Although 21% of the sample evidenced clinically significant levels of depression at 6 months,the majority (61%)had extremely low levels of depression throughout the study.A comparable pattern was recently observed in a large sample of hospitalized survivors of the 2003 server acute respiratory syndrome(SARS) epidemic in Hong Kong.In keeping with the frightening nature of the epidemic,latent class analyses revealed that an unusually large proportion of the sample (42%)had chronically low levels of psychological functioning across the first 18 months after hospitalization.Nonetheless,Despite the epidemic's impact ,there were still almost as many individuals(35%)with consistently high levels of psychological functioning across the same time period(Bonanno et al.,2008).Resilience across the LifespanHow strongly do lifespan developmental factors influence resilience? Is resilience to potentially traumatic events observed to a similar degree in children and in older adults? Somewhat surprisingly, there are relatively few data on trauma and grief reactions among children, and results have provided somewhat mixed conclusions. In their study of children’s reactions to Hurricane Andrew, a Category 4 storm, La Greca, Silverman,Vernberg, and Prinstein (1996) found that 55.8% fell into the categories of mod 55.8% fell into the categories of moderate to very severe PTSD 3 mouths after the storm, declining to 33.5% at 10 mouths. On theother hand, 44.2% of the sample showed minimal to absent symptoms at 3 mouths, indicating that a substantial proportion most likely showed resilience. Consistent with the adult literature, the most robust predictor of PTSD scores at 3 mouths was an exposure variable, accounting for 15% of the variance. These findings would seem to suggest that children, when compared to adults, are equally and perhaps more vulnerable to PTSD.However,this study used a self-report measure that does not map directly onto a PTSD diagnosis. The researchers also employed a convenience sample. By contrast, studies using representative samples and diagnostic interviews have suggested PTSD prevalence rates for children that are equal to or substantially lower than those of adults. For example, another investigation of Hurricane Andrew found that among children ages 12-17 only 2.9% of males and 9.0% of females met criteria for a PTSD diagnosis (Garrison et al.,1995). Interestingly, increased age was associated with higher rates of PTSD, underlining the role of developmental factors. A similar prevalence of PTSD was observed (4.5%) in a study of child and adolescent survivors of the 1999 earthquake in Ano Liosia,Greece (Roussos et al.,2005). Moreover, a recent epidemiological investigation of PTSD among children and teenagers, ages 9-16,found even lower prevalence rates using a diagnostic interview measure and a representative sample (Copeland et al.,2007). In a longitudinal design spanning 8 years, less than 0.5%of children met criteria for a PTSD diagnosis,despite being exposed to a variety of extreme stressors(violence,interpersonal loss,sexual trauma).Together,these findings suggest that children cope well with isolated potentially traumatic events and only rarely develop full-blown PTSD .Nevertheless,a remaining question is different from that in adults (Perrin,Smith,&Yule,2000).In contrast to PTSD,studies of children's bereavement reactions report levels of complicated grief similar to those of adults(Christ,2000).As we discuss below,however,it is important to keep in mind that the question of adjustment to loss and to other extremely aversive experiences is in many ways more complex among children;therefore,these proportions should be considered with caution.What about PTSD and grief in older adults?Investigations have generally suggested that increased age protects against dysfunction related to loss or to other potentially traumatic events.For example,Phifer(1990)found that older adults with high exposure to a severe flood were less vulnerable to psychological distress than were middleaged adults with Similar exposure.Although a comparison of younger and older adults' reactions to the 1988 earthquake in Armenia failed to reveal differences in overall PTSD symptoms(Goenjian et al,1994),other studies have also suggested that older adults experience fewer symptoms than do younger adults in response to various natural disasters,including a tornado(Bell,1978)and the Buffalo Creek dam collapse (Green etal.,1990).Moreover,in their meta-analysis of PTSD risk factors,Brewin,Andrews,and Valentine(2000)reported that older age is modestly associated with less PTSD,though。