Cumulative Trauma and Posttraumatic Stress Disorder Among Children Exposed to the 9/11 World Trade Center Attack

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1 American Journal of Orthopsychiatry Copyright 2008 by the American Psychological Association 2008, Vol. 78, No. 1, /08/$12.00 DOI: / Cumulative Trauma and Posttraumatic Stress Disorder Among Children Exposed to the 9/11 World Trade Center Attack Elizabeth Mullett-Hume, PhD, Daphne Anshel, PhD, Vivianne Guevara, BA, and Marylene Cloitre, PhD New York University Child Study Center Two and one-half years after the September 11, 2001 World Trade Center attack, 204 middle school students in an immigrant community located near Ground Zero were assessed for posttraumatic stress disorder (PTSD) symptoms as influenced by dose of exposure to the attack and accumulated lifetime traumas. Ninety percent of students reported at least one traumatic event other than 9/11 (e.g., community violence) with an average of 4 lifetime events reported. An interaction was obtained such that the dose response effect depended on presence of other traumas. Among students with the lowest number of additional traumas, the usual dose-response pattern of increasing PTSD symptoms with increasing 9/11 exposure was observed; among those with medium to high cumulative life trauma, PTSD symptoms were substantially higher and uniformly so regardless of 9/11 exposure dose. Results suggest that traumas that precede or follow mass violence often have as much as if not greater impact on long-term symptom severity than high-dose exposure to the event. Implications regarding the presence of continuing or previous trauma exposure for postdisaster and early intervention policies are discussed. Keywords: posttraumatic stress, children, terrorism, September 11th, immigrants Elizabeth Mullett-Hume, PhD, Daphne Anshel, PhD, Vivianne Guevara, BA, and Marylene Cloitre, PhD, New York University Child Study Center. This work was supported by a grant from the 9/11 American Red Cross Fund. Correspondence: Marylene Cloitre, PhD, Institute for Trauma and Resilience, NYU Child Study Center, 215 Lexington Avenue, 16th Floor, New York, NY marylene.cloitre@med.nyu.edu Several pediatric studies of the effects of incidents of large-scale violence have found that as in adult samples, severity of posttraumatic stress symptoms is positively correlated with severity of exposure to the event. This dose response effect among children has been found following a variety of events such as the Oklahoma City bombing (Pfefferbaum et al., 1999, 2000), sniper attacks (Nader, Pynoos, Fairbanks, & Frederick, 1990; Pynoos, Frederick, Nader, & Arroyo, 1987; Schwarz & Kowalski, 1991), terrorist attacks during civil unrest (Saigh, Yasik, Sack, & Koplewicz, 1999) and the World Trade Center (WTC) attack (Hoven et al., 2005). The purpose of this study was to evaluate the longer term effects of exposure dose on children directly exposed to the September 11, 2001, WTC attack, if any, and to assess the impact of 9/11 on posttraumatic stress symptoms in relation to other traumatic stressors that the children reported having experienced. Attention to the potential influence of exposure to violence and other traumatic stressors within the children s immediate environment was prompted by findings from a study commissioned by the New York City Department of Education that reported that the majority (64%) of public school students in New York had experienced exposure to at least one violent event independent of the WTC attack on 9/11 (Hoven et al., 2002). This finding is consistent with epidemiological studies of urban environments in which rates of trauma exposure are high and growing, particularly and disproportionately in younger, school-age populations (Anderson et al., 2001; DeVoe, Peter, Noonan, Snyder, & Baum, 2005). Although it has been established that youths from urban communities are particularly at risk for trauma exposure (Breslau, Wilcox, & Storr, 2004), recent studies have indicated that immigrant children are highly exposed to a range of traumatic stressors (Jaycox et al., 2002; Ozer & McDonald, 2006). The most frequently reported events experienced by immigrant children are domestic violence, community violence, and sudden or unexpected death or illness of family members or those close to them (Breslau et al., 2004; Jaycox et al., 2002; Ozer & Mc Donald, 2006; Singer, Anglin, Song, & Lunghofer, 1995). A history of previous trauma exacerbates risk for posttraumatic stress disorder (PTSD; Brewin, Andrews, & Valentine, 2000). There is also evidence that additional traumas following an event increase the risk of PTSD related to it (Lloyd & Turner, 2003; Yehuda et al., 1995), suggesting that the presence of multiple and ongoing traumatic stressors surrounding a single high-magnitude event (e.g., terrorist attack or natural disaster) may create additional social and psychological burdens on children. This possibility has implications for postdisaster child mental health prevention and intervention programming, for which there is as yet little empirical evidence on which to base guidelines or program recommendations. We systematically assessed history of trauma other than 9/11 WTC exposure to identify the extent and nature of violence exposure and other traumas among Ground Zero children living in an impoverished immigrant community and examined its potential impact on their 9/11 WTC exposure-related symptomatology. Method Study Participants A total of 204 students participated in the study. Students were from three Chinatown middle schools located within 10 blocks of 103

2 104 MULLETT-HUME ET AL. the WTC Tower attack on September 11, The majority of students (89.6%) at the three schools receive free lunch, with most students reporting that their parents work in the textile, apparel, or food service related industries. For all three schools combined, the mean age of the students was 13.0 years old (SD 1.06) with a range of 12 to 16; approximately 62% of the sample was female. The ethnic backgrounds of the students were entirely minority and were as follows: 81% Asian American, 9% Hispanic, 6% African American, and 4% either biracial or from other backgrounds. Approximately 67% of the students were born in the United States. For those who had immigrated to the United States, the mean age at the time of immigration was 5.04 years (SD 2.58). All students in the study spoke English. Students who did not live in the New York City metropolitan area at the time of 9/11 were excluded from the current analyses (n 12). Procedures Students were part of a study examining the effectiveness of a culturally sensitive school-based, universal prevention program for middle schools in the Chinatown community. Permission was obtained to conduct the study from the New York City Department of Education and the New York University School of Medicine Institutional Review Board (IRB). All questionnaires were designed to be appropriate for use with students a minimum of two grade levels younger than participants and the students teachers were asked to review the questionnaires to assess readability for this population. After parental consent and student assent were obtained, trained New York University staff administered selfreport questionnaires to groups of 7 to 20 students in classroom settings. Staff explained the purpose of the study and read the directions for the measures. Students were encouraged to ask any questions they may have had as they completed the surveys. Measures The New York University Child and Adolescent Stressors Checklist Revised (NYU CASC; Cloitre, Morin, & Silva, 2002). The NYU CASC is a 66-item yes no self-report questionnaire that queries about exposure to various forms of trauma and life stressors. A section of the questionnaire consists of 7 items devoted to exposure to various aspects of the WTC attack. In addition the measure includes six categories of trauma defined by the Diagnostic and Statistical Manual of Mental Disorders (fourth ed., or DSM IV; American Psychiatric Association, 1994) and three categories of life adversities (e.g., divorced parents). For the purposes of this study, only traumatic stressors, that is, events with characteristics defined as potentially traumatic by the DSM IV Criterion A, were included: domestic violence (4 items); community and school violence (11 items); significant illness or death of parents, siblings or close family members (6 items); accidents and injuries to self (6 items); natural disasters (8 items); and war (4 items). A final category of other was available in which children were invited to include events they considered traumatic. In accordance with Department of Education IRB policy, no questions regarding sexual or physical abuse were included. There were no participants who experienced the death of a parent or family member as a result of 9/11. Following previous research (e.g., Pfefferbaum et al., 2000), we defined cumulative trauma as the sum of endorsements (yes vs. no) for each item in the questionnaire. The Child PTSD Symptom Scale (CPSS; Foa, Johnson, Feeny, & Treadwell, 2001). The CPSS is a 17-item self-report questionnaire that assesses the frequency of PTSD symptomatology on a 4-point scale ranging from 0 (not at all) to3(almost always), based on the 17 symptoms identified in the DSM IV PTSD diagnosis. It includes 7 items measuring the presence of functional impairment (rated yes or no), permitting use of an algorithm to determine PTSD diagnosis by reporting impairment and sufficient symptoms from all three clusters (one reexperiencing, two arousal, and three avoidance symptoms). In the current study, students were directed to report PTSD symptoms and functioning as related to Criterion A stressors: direct exposure to the September 11, 2001, WTC attack. The CPSS has high convergent and divergent validity and internal consistency ratings of.89 for overall ratings of PTSD symptomatology and.89 for the Functional Impairment subscale (Foa et al., 2001). Its validity has been reported in three publications on minority middle school children (Jaycox et al., 2002; Kataoka et al., 2003; Stein et al., 2003). In this study sample, Cronbach s alpha was.89 for the 17 PTSD symptoms items and.90 for the Functional Impairment subscale. WTC Exposure Results Figure 1 presents frequencies regarding the nature of exposure to the destruction of the 9/11 WTC attack. All students were in the Ground Zero area at the time of the attack. The most commonly endorsed item was seeing the towers fall (51%), followed by seeing the planes hit the towers (42%) and seeing bodies falling (28%). Excluding Item 7, which taps indirect (excessive media) exposure, the mean number of direct 9/11 WTC exposures was 2.60 (SD 1.67, range 0 to 6), with 12% of the students endorsing one direct exposure item, 14% endorsing two items, and 32% endorsing three or more items. Additional Trauma Exposure The vast majority (90%) of the sample had experienced one or more of the traumatic events that were assessed in addition to exposure to the 9/11 WTC attack. Ten percent were exposed to a single trauma, 18% were exposed to two, 12% were exposed to three, and 49% were exposed to four or more traumatic events. The average number of traumatic events experienced in the sample was 4.36 (SD 3.38, range 0 to 15). Thirty percent reported experiencing community violence; 30% witnessed domestic violence; 29% reported significant illness or death of close family members; 50%, accidents or injuries to self; 22%, natural disasters; 2.5%, war; and 8%, other traumas. PTSD Diagnosis, Symptom Severity, and Functional Impairment Following the DSM IV guidelines for PTSD, including the presence of functional impairment, 35% of the sample met criteria for the disorder according to the CPSS. In addition, as defined in previous studies using this same measure (Foa et al.,

3 CUMULATIVE TRAUMA AND WTC EXPOSURE IN CHILDREN % Students Saw Planes Saw WTC Fall People Falling Saw Someone Hurt or Killed Body Parts Surrounded by Debris Excessive Media Exposure Figure 1. attack. Percent of students with various types of direct exposure to the 9/11 World Trade Center (WTC) 2001; Jaycox et al., 2002; Kataoka et al., 2003), 44% of students were identified as having moderate levels of PTSD symptoms ( 11 point cutoff), regardless of meeting the criteria for the disorder. The average CPSS score was (SD 8.75), with a range from 0 to 36. Almost half of the students endorsed experiencing functional impairment across a variety of domains, including difficulties completing schoolwork (49%), problems in their relationships with friends (48%), difficulties having fun and participating in hobbies (47%), difficulties in their relationships with family (44%), and difficulties with chores and duties (43%). A total of 47% reported that their symptoms were affecting their general happiness with life. The correlation between number of PTSD symptoms and functional impairment items reported (excluding the item having difficulty with prayers because of the potential absence of such activities in some families) was significant (r. 26, p.01). Correlations Correlations among PTSD symptoms, gender, ethnicity, cumulative life traumas (CLTs), 9/11 WTC exposure, and their interaction are provided in Table 1. Of note, no correlation between 9/11 WTC exposure and history of cumulative life trauma was obtained, indicating that the WTC attack exposures occurred randomly, not systematically, and were unrelated to other types of stressors or traumatic experiences. The correlation between 9/11 WTC exposure and PTSD symptoms (CPSS scores) was marginal (r.11, p.06). However, the relationship between PTSD symptoms and the interaction of 9/11 Table 1 Correlations of Posttraumatic Stress Disorder (PTSD) Symptoms, Gender, Ethnicity, Cumulative Life Trauma (CLT), World Trade Center (WTC) Exposure, and the Interaction Between WTC Exposure and Criterion A Events Variable r p r p r p r p r p 6(r) 1. PTSD symptoms 2. Gender Ethnicity CLT WTC exposure WTC Exposure CLT

4 106 MULLETT-HUME ET AL. WTC exposure and number of CLTs was significant (r.24, p.001). Predictions of WTC Exposure, CLTs, and PTSD Symptoms We conducted a hierarchical multiple regression analysis to test the relationship between CLTs, 9/11 WTC exposure, and their interaction in predicting posttraumatic stress symptomatology. Gender and ethnicity were entered first as control variables, followed by CLT, 9/11 WTC exposure, and the interaction between CLTs and WTC exposure. In the final model (Step 5), ethnicity and gender and 9/11 WTC exposure by itself did not significantly predict PTSD symptoms. Only CLTs and the interaction between CLT and 9/11 WTC exposure were significant (see Table 2). The interactions between direct 9/11 WTC exposure and cumulative life events are presented in Figure 2. Regression lines at Step 5 were plotted using procedures recommended by Aiken and West (1991) for representative high ( 1 SD), medium (between 1 SD and 1 SD), and low ( 1 SD) levels of CLTs. The mean CLT score was 4.36 (SD 3.38). At the high level ( 1 SD), the mean was 9.79 (SD 1.85); at the medium level, 3.59 (SD 1.98); and at the low level ( 1 SD), 00.0 (SD 00.0). This figure, which controls for all other variables, illustrates that the number of direct 9/11 WTC exposures had significant impact on PTSD symptomatology among students who had experienced the lowest number of other life traumas. However, for students who had experienced a high number of other traumas, increasing dose of 9/11 WTC exposure did not influence PTSD symptomatology. The high CLT group had PTSD scores equivalent to those of students with the highest level of exposure to 9/11 in the low CLT group. PTSD Characteristics by Trauma Group Although most of the sample had experienced at least one significant trauma other than the 9/11 WTC attack, there was substantial variability in the total number of traumas reported, and that variability is reflected in the clinical characteristics of three groups defined by the interaction model. The children in the high CLT group were worse off as measured by PTSD symptom severity and PTSD diagnosis according to the CPSS. The high CLT Table 2 Hierarchical Multiple Regression Analysis of Posttraumatic Stress Disorder (PTSD) Symptom Severity Step entered Model F Step Final step Total R 2 R 2 B a 1. Gender 5.70 * * Ethnicity Cumulative life trauma *** *** 1.56 ***.60 *** (CLT) 4. World Trade Center 9.37 *** (WTC) exposure 5. WTC Exposure CLT 8.43 *** *.19 *.38* a Unstandardized regression weights for final equation. * p.05. *** p.001. group had an average CPSS score of (SD 8.86), which was significantly higher than those of the medium (10.77, SD 8.86) and low CLT groups (5.95, SD 4.88); the medium CLT group score was in turn higher than that of the low CLT group, F(2, 203) 12.41, p.001. Rates of PTSD according to the CPSS differed among the three groups, with the high CLT group having a rate of 50% compared with 35% in the medium CLT group and 9% in the low CLT group, 2 (2, N 202) 16.1, p.001. Discussion The findings of the current study indicate that the long-term sequelae of direct exposure to the 9/11 WTC attack differed for children depending on their history of trauma exposure. For those with a relatively low accumulation of other life traumas, a significant dose response effect in PTSD symptom severity was obtained 2.5 years postevent. The dose response relationship is consistent with past research (La Greca, Silverman, & Wasserstein, 1998; Pfefferbaum, 1997; Pfefferbaum et al., 2000) and suggests the enduring impact of a single-incident trauma on the mental health of children who have experienced minimal exposure to other traumatic events. In contrast, children with medium to high levels of CLT evidenced significantly higher levels of 9/11 PTSD symptoms, but the severity of symptoms was best predicted by the accumulation of other life traumas rather than the dose of 9/11 exposure, which was essentially irrelevant. The study results suggest that a history of multiple traumas is a significant and potentially more potent risk factor for psychiatric impairment than the severity of exposure to the index event. The findings provide evidence for the importance of assessing trauma history in the wake of large-scale or mass traumas, particularly among minority and immigrant communities who are likely to experience higher rates of traumatization and psychiatric burden (Breslau et al., 2004). The study findings are a call to appreciate the impact of traumatic stressors in children s everyday lives and the need to provide attention and resources to these problems, even as we prepare programming and strategies to respond to future events of terrorism or disaster. The findings also have direct implications for postdisaster planning. Intervention and prevention programs need to be adapted to the social and environmental conditions of the community receiving services. Researchers have documented the efficacy of symptom-focused therapies for children and adolescents exposed to single-event community trauma (March, Amaya- Jackson, Murray, & Schulte, 1998). However, programming for children who have lived and will continue to live in high-stress environments requires strategies that include skills building to maintain gains made in symptom reduction and to enhance resilience in the face of expected continuing and future adversities (Koplewicz, Cloitre, Reyes, & Kessler, 2004; Saltzman, Pynoos, Layne, Steinberg, & Aisenberg, 2001). Limitations Several design limitations should be kept in mind in interpreting the results of this study. First, we do not know the time course of the other traumas relative to September 11, The survey was implemented 2.5 years after the WTC attack; thus, the additional

5 CUMULATIVE TRAUMA AND WTC EXPOSURE IN CHILDREN 107 Figure 2. Interaction effects of direct World Trade Center (WTC) and cumulative life trauma in predicting severity of posttraumatic stress disorder (PTSD) symptoms. traumas reported could have occurred either before or after September 11. However, previous research has indicated that stressors previous to or after an index event can create vulnerability to the development of PTSD symptoms, with those after the event creating risk for symptom maintenance, symptom exacerbation, or even late onset of the symptoms. Second, in accordance with Department of Education IRB policy, we were required to remove questions about physical and sexual abuse, which might have produced an underestimation of lifetime cumulative trauma. In addition, the assessment was cross-sectional and occurred at only one point in time. Future research should prospectively assess the impact of terrorist and other events of mass violence at multiple time points to identify potential critical windows of time within which to administer interventions (Feerick & Prinz, 2003). Finally, other factors not included in this analysis, such as comorbidity and social support, have the potential to modify the results either mitigating or exacerbating the impact of multiple traumatization surrounding a high-magnitude trauma of mass violence. Last, the review of the interaction effect as depicted in Figure 2 may lead to the concern that the flat slope in the high CLT group reflects a ceiling effect in which the dose response among the highly traumatized children is obscured owing to lack of sensitivity of the instrument in the higher ranges of the phenomena it measures. However, the CPSS has been used in other studies in which higher scores have been obtained (Stein et al., 2003). In addition, in this study there was a range of scores on the instrument from 0 to 36, suggesting that the mean score of for this group was not found because of a ceiling effect. The overall rate of PTSD reported in this study (35%) is similar to that obtained in the only other study we know of that used the CPSS to assess PTSD in minority immigrant youth (29%; Jaycox et al., 2002; Kataoka et al., 2003). Summary and Implications This study has found that at 2.5 years post-9/11, a significant proportion of children were experiencing substantial PTSD symptoms. In addition, in this minority and immigrant population, multiple traumatization was the rule rather than the exception, and the presence of other traumas had a critical influence on PTSD symptomatology, with estimates of a PTSD diagnosis ranging from 9% to 50% depending on presence of other traumatic stressors. The implications for disaster planning are that needs assessments, although brief, should include inquiry about history of traumatic stressors both before and after the index event. In addition, optimal programming postdisaster must be flexible, depending on the child s history and social context. For many communities, interventions and prevention will need to include strategies for coping with a multiplicity of past and ongoing traumas and life stressors. The relevance of this issue is immediate, as health and mental health providers are confronted with the development of ongoing assessment and prevention programming for the thousands of children and families who survived recent highmagnitude disasters such as Hurricane Katrina and the earthquake

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