Comparing Stress Responses to Terrorism in Residents of Two Communities Over Time

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1 Comparing Stress Responses to Terrorism in Residents of Two Communities Over Time Betty Pfefferbaum, MD, JD, Rose L. Pfefferbaum, PhD, MPH, Elaine H. Christiansen, PhD, John K. Schorr, PhD, Robert D. Vincent, PhD, Sara J. Nixon, PhD, Carol S. North, MD, MPE To explore psychological resilience and recovery following the 1995 Oklahoma City bombing, we assessed reactions to the incident in residents of Oklahoma City and a comparison city over 3 years. Concerned that the bombing might have preconditioned Oklahoma City residents to adverse reactions to later events, we also examined psychological responses to the September 11 terrorist attacks on Oklahoma City residents. We surveyed psychological responses to the bombing in residents of Oklahoma City and Indianapolis in 1995, 1996, and 1998 and psychological responses to the September 11 attacks in Oklahoma City as part of a national sample in Univariate and bivariate analyses were conducted. Oklahoma City residents reported significantly more posttraumatic and general stress compared to Indianapolis residents in the months following the bombing, but differences decreased over time. Oklahoma City respondents were no different from the rest of the nation on most measures after the September 11 attacks. Results suggest optimism regarding psychological resilience and recovery from terrorism in affected communities and nationally. [Brief Treatment and Crisis Intervention 6: (2006)] KEY WORDS: community resilience, disasters, Oklahoma City bombing, posttraumatic stress, terrorism. Focusing for the most part on adverse psychological responses, studies have raised concern about the mental health effects of the September 11, 2001, terrorist attacks on the general population of New York City and the nation (Galea et al., 2002, 2003: Schlenger et al., 2002; Schuster et al., 2001; Silver, Holman, McIntosh, Poulin, & Gil-Rivas, 2002; Stein et al., 2004). Galea et al. (2002) found a greater prevalence of posttraumatic stress disorder (PTSD) symptoms in Manhattan residents most directly affected by the World Trade Center attacks through residence in the From the Department of Psychiatry and Behavioral Sciences, College of Medicine, University of Oklahoma Health Sciences Center (B. Pfefferbaum), the Liberal Arts Department, Phoenix College (R. L. Pfefferbaum), The Gallup Organization (Christiansen), the Department of Sociology, Stetson University (Schorr), the College of Public Health, University of Oklahoma Health Sciences Center (Vincent), the Department of Psychology, University of Kentucky (Nixon), and the Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas (North). Contact author: Betty Pfefferbaum, Department of Psychiatry and Behavioral Sciences, College of Medicine, University of Oklahoma Health Sciences Center, 920 Stanton L. Young Boulevard, WP-3470, Oklahoma City, OK betty-pfefferbaum@ouhsc.edu. doi: /brief-treatment/mhj017 Advance Access publication April 7, 2006 ª The Author Published by Oxford University Press. All rights reserved. For permissions, please journals.permissions@oxfordjournals.org. 137

2 PFEFFERBAUM ET AL. vicinity or lost possessions and also found that a substantial number of individuals who were not directly affected met the investigators definition of probable PTSD. Their definition focused on PTSD symptoms without specifically addressing the stressor criterion and used 2-week, rather than the required 1-month, duration criterion for the disorder. Thus, technically, many of these individuals would not have qualified for a diagnosis of PTSD, perhaps explaining, in part at least, the dramatic decline in probable PTSD in this sample within 6 months (Galea et al., 2003). In a national longitudinal study, Stein et al. (2004) found that whereas 30% of respondents originally surveyed in the days after September 11 showed improvement in symptoms, 16% continued to experience distress 2 months later. Silver et al. (2002) also found a decrease in posttraumatic stress symptoms at 6 months in their national sample. To our knowledge, data on the course of recovery beyond the first year have not been published. More than a decade ago, the 1995 Oklahoma City bombing raised public awareness of terrorism. A team from the Oklahoma State Department of Health, the University of Oklahoma Health Sciences Center, and The Gallup Organization in Lincoln, NE, examined the psychological responses to this disaster by conducting three general population surveys in Oklahoma City and Indianapolis a community of similar size and demographics in 1995, 1996, and These surveys represented three crosssectional studies with new samples drawn each time rather than a longitudinal study using the same sample. Thus, we are able to report findings relative to the general population in both communities at each time beginning in the early months after the attack and over the course of recovery, but we are not able to track the reactions of individuals over time. As a means of assessing the potential psychological vulnerability of Oklahoma City residents to future events, we conducted a fourth national survey in 2002 to assess responses following the September 11 attacks and compared responses in OklahomaCity tothose in the restof the nation. Methods Sampling and Survey A sample of telephone numbers was created for each survey by randomly selecting the first eight digits of a telephone number, known as a block (the area code and the three-digit exchange plus the next two digits), from among all such blocks in the Oklahoma City and Indianapolis metropolitan statistical areas (MSAs) that contained at least one listed residential number. The last two numbers were randomly selected to obtain a full ten-digit telephone number. Within each contacted household, one adult, aged 18 years or older, was randomly selected from adults living in the household. Up to five attempts were made, at different times and on different days, to contact someone at each phone number generated. Data were weighted to account for unequal selection probabilities at both the household and individual respondent level. Data were also adjusted to reflect the proportion of Whites and non-whites, Hispanics and non-hispanics, and men and women by age groups in the general population. The Oklahoma City samples represented the adult population of approximately 704,000 individuals living in households with telephones in the six-county Oklahoma City MSA. The adult population of approximately 921,000 individuals living in households with telephones in the nine counties comprising the Indianapolis MSA provided a comparison sample. Oklahoma City, with a per capita household income of $21,000, had an unemployment rate of 5.4% in The unemployment rate in 138 Brief Treatment and Crisis Intervention / 6:2 May 2006

3 Comparing Stress Responses to Terrorism Indianapolis was 4.2%, and the per capita household income was $23,300. The 2002 study assessed a cross-sectional national sample with oversamples in Oklahoma City and in New York City and Washington, DC, where more directly affected individuals were likely to reside. See Table 1 for a description of the samples. Data Analysis We conducted univariate and bivariate analyses of percentages using z tests on unweighted sample sizes. A 95% confidence interval, adjusted for multiple comparisons, was used to identify statistical differences. Dichotomous variables were constructed for use in the analyses to compare the two highest categories with the lowest categories on a continuum of response options presented to respondents. Missing values were excluded from all analyses. Variables We assessed the same basic constructs in all three surveys, but in some instances we used different variables, limiting direct comparison over time. We present here variables for which we had measurements in more than 1 year. Posttraumatic Stress. We measured posttraumatic stress using variables representing symptoms in each of the three PTSD diagnostic symptom group clusters intrusive reexperiencing, avoidance/numbing, and arousal. The survey queried items since the bombing in 1995 and 1996, and in the past year in In all years, a scale with five options from never to very often was used. General Stress. We measured general stress using a four-point scale from almost no stress at all to a lot of stress and referenced since the bombing in 1995 and as a result of the bombing in 1996 and in Oklahoma City in General stress was not measured in Indianapolis in Survey. In the 2002 survey, posttraumatic stress items referenced the September 11 attacks instead of the Oklahoma City bombing TABLE 1. Sample Characteristics Race (% of unweighted cases) Survey dates Sample size (response rate) Gender (% of unweighted cases) White African American American Indian Other a July August 1995 Oklahoma City 1,010 (46%) 43 male Indianapolis 750 (46%) 46 male September November 1996 Oklahoma City 1,020 (40%) 39.6 male Indianapolis 402 (37%) 47.5 male October December 1998 Oklahoma City 1,022 (35%) 44.3 male Indianapolis 400 (35%) 43.5 male March April 2002 Oklahoma City 508 (34%) 61.0 male 89.2 (10.8 non-white and 3.1 Hispanic) Rest of the nation 2,011 (66%) 47.1 male 81.0 (19.0 non-white and 6.7 Hispanic) a Includes other minorities and those who did not report race. Brief Treatment and Crisis Intervention / 6:2 May

4 PFEFFERBAUM ET AL. with questions comparing the last month to before September 11 and options ranging from never to very often. Stress since the September 11 attacks was established with four options from almost no stress at all to a lot of stress. Oklahoma City participants were compared to participants in the rest of the country, determined by excluding Oklahoma City from our national sample. Results We found a number of significant differences between Oklahoma City and Indianapolis in These differences represented all three of the symptom group clusters associated with PTSD intrusive reexperiencing, avoidance/ numbing, and arousal as well as global perception of stress. Fewer significant differences persisted in 1996 and There were no significant differences between respondents in Oklahoma City and the rest of the nation on items in 2002 except for a significantly lower prevalence of intrusive thoughts in Oklahoma City respondents (Table 2). Discussion Like the September 11 studies, our study found that Oklahoma City residents reported posttraumatic stress and general stress responses in the months following the Oklahoma City bombing. Indianapolis residents had similar responses, though there were significant differences between the two communities in items representing each of the three PTSD symptom group clusters. These differences may have resulted from the pervasive stimulus cues in Oklahoma City at the time of the study. In their study of survivors directly exposed to the 1995 bombing, North et al. (1999) found endorsement of intrusive reexperiencing nearly universal during the 6 months after the incident and that these responses generally were not associated with pathology or impaired functioning if not also accompanied by significant avoidance/numbing. Thus, although differences in intrusive reexperiencing (in the form of intrusive thoughts) between Oklahoma City and Indianapolis persisted across all three time periods, these differences in our samples of individuals with primarily indirect or remote exposure to the incident are likely to represent normative distress if not accompanied by significant avoidance/numbing. The significantly higher endorsement of purposeful avoidance of reminders in Oklahoma City compared to Indianapolis, with differences that did not remain significant in 1996, may actually represent a healthy adaptation in the absence of significant differences in other avoidance/numbing measures. Differences in self-reported startle reactions were significant in 1995 and 1996; this item was not measured in Of note, neither temper nor concentration problems were elevated in Oklahoma City in 1995 or 1996, compared to Indianapolis, even in the first months after the bombing. The paucity of statistically significant differences in 1998, including the failure to find a statistically significant difference in general stress, suggests a trajectory of psychological recovery from both pathological symptoms and nonspecific distress. The difference in the item reflecting loss of interest in 1996 is perplexing; regardless, the difference did not persist in We are precluded from making certain comparisons across the three studies, however, because we did not measure all of the items in all years and because of differences in wording of items in the three studies. We were concerned that the bombing might have preconditioned Oklahoma City residents to adverse reactions to later events. Our results related to the September 11 attacks failed to distinguish Oklahoma City from the rest of the nation on most items, which is consistent 140 Brief Treatment and Crisis Intervention / 6:2 May 2006

5 Comparing Stress Responses to Terrorism TABLE 2. Mean Scores (Standard Deviation) on Items for Each Survey % Weighted cases endorsing (confidence interval) Item Year Oklahoma City Indianapolis Rest of nation Intrusive reexperiencing Intrusive thoughts about the incident Very often/fairly often since bombing a (4.2) 11.9 (3.5) Very often/fairly often since bombing a (4.1) 4.5 (3.2) Very often/fairly in the past year a (3.4) 6.4 (3.5) Very often/fairly often in past month compared to (5.2) c Had dreams or nightmares about the incident Very often/fairly often since bombing a (1.6) 0.9 (1.0) Very often/fairly often since bombing (1.3) 0.3 (1.0) Very often/fairly often in past year (1.0) 0.9 (1.4) very often/fairly often in past month compared to (2.5) Avoidance/numbing Avoided situations that reminded you of the incident Very often/fairly often since bombing a (3.4) 5.8 (2.5) Very often/fairly often since bombing (2.3) 2.8 (2.5) Yes (3.3) Lost interest in things that used to be interesting Very often/fairly often since bombing (2.3) 5.2 (2.4) Very often/fairly often since bombing a (2.5) 3.1 (2.7) Very often/fairly often in past year (2.4) 6.2 (3.5) Very often/fairly often in past month compared to (3.0) Felt isolated from other people Very often/fairly often since bombing (2.4) 1.8 (2.0) Very often/fairly often in past year (2.2) 4.0 (2.8) Very often/fairly often in past month compared to (2.9) Felt there was no point in thinking about the future Very often/fairly often since bombing (1.9) 1.8 (2.0) Very often/fairly often in past year (3.2) 3.9 (2.8) Very often/fairly often in past month compared to (2.6) Arousal Had sleep disturbance Had trouble sleeping very often/fairly often (2.9) 9.1 (3.1) since the bombing Sleep was restless most of time/often in past week (4.1) 17.3 (5.8) Very often/fairly often in past month compared to (4.1) Lost your temper Very often/fairly often since bombing (2.7) 8.4 (3.0) Brief Treatment and Crisis Intervention / 6:2 May

6 PFEFFERBAUM ET AL. TABLE 2 continued. Mean Scores (Standard Deviation) on Items for Each Survey % Weighted cases endorsing (confidence interval) Item Year Oklahoma City Indianapolis Rest of nation 8.0 (1.9) 9.6 (2.0) 36.1 (3.3) Very often/fairly often since bombing (2.5) 4.1 (3.1) Had trouble concentrating/keeping your mind on what you were doing Very often/fairly often since bombing (2.6) 7.6 (2.9) Most of the time/often in past week (3.8) 12.3 (5.1) Very often/fairly often in past month compared to (3.6) Startled easily Very often/fairly often since bombing a (3.0) 5.4 (2.4) Very often/fairly often since bombing a (3.2) 5.8 (3.6) Very often/fairly often in past month compared to (3.8) General stress A lot/moderate amount of stress since the bombing a (4.6) 30.2 (5.0) A lot/moderate amount of stress as a result of the a (3.9) 10.4 (4.7) bombing A lot/moderate amount of stress as a result of the (3.0) bombing A lot/moderate amount of stress since the (5.8) September 11 attacks b a Oklahoma City score significantly different from Indianapolis score within study year (p,.05). b Responses reference the September 11 attacks rather than the Oklahoma City bombing. c Oklahoma City score significantly different from the rest of the nation in 2002 (p,.05). with psychological recovery and community resilience. The significantly lower prevalence of intrusive thoughts of the September 11 attacks in Oklahoma City respondents compared to the rest of the nation may reflect the fact that the lives of Oklahoma City residents had been so influenced by the 1995 bombing that intrusive thoughts referenced those experiences rather than September 11, which was the subject of the survey item. It is possible that Oklahoma City residents who were directly exposed to the bombing and those who knew someone directly affected may have experienced more pronounced responses to the September 11 attacks than indirectly exposed Oklahoma City residents or remotely exposed individuals in the rest of the nation. Conclusions Our findings suggest that residents in communities exposed to terrorist assault can be optimistic about the potential for psychological recovery and that their reactions are likely to be time limited and not indicative of enduring psychopathology. It is possible that populations that suffer disruption in their neighborhoods, employment, or economic loss or other secondary forms of exposure to community disaster will face greater difficulty than Oklahoma City residents experienced. The suggestion of psychological resilience and recovery does not obviate the need to develop mental health prevention strategies and support systems as part of the infrastructure of preparedness, however. 142 Brief Treatment and Crisis Intervention / 6:2 May 2006

7 Comparing Stress Responses to Terrorism Strategies and systems should be tailored to the type and extent of exposure and should address both immediate and enduring mental health consequences. Acknowledgments Supported under Award Number MIPT from the National Memorial Institute for the Prevention of Terrorism (MIPT) and the Office of State and Local Government Coordination and Preparedness, U.S. Department of Homeland Security. Conflict of Interest: Points of view in this document are those of the authors and do not necessarily represent the official position of MIPT or the U.S. Department of Homeland Security. The Centers for Disease Control and Prevention, the Oklahoma State Department of Health, and The Gallup Organization also contributed support for this study. References Galea, S., Ahern, J., Resnick, H., Kilpatrick, D., Bucuvalas, M., Gold, J., et al. (2002). Psychological sequelae of the September 11 terrorist attacks in New York City. The New England Journal of Medicine, 346, Galea, S., Vlahov, D., Resnick, H., Ahern, J., Susser, E., Gold, J., et al. (2003). Trends of probable posttraumatic stress disorder in New York City after the September 11 terrorist attacks. American Journal of Epidemiology, 158, North, C. S., Nixon, S. J., Shariat, S., Mallonee, S., McMillen, J. C., Spitznagel, E. L., et al. (1999). Psychiatric disorders among survivors of the Oklahoma City bombing. Journal of the American Medical Association, 282, Schlenger, W. E., Caddell, J. M., Ebert, L., Jordan, B. K., Rourke, K. M., Wilson, D., et al. (2002). Psychological reactions to terrorist attacks: Findings from the National Study of Americans Reactions to September 11. Journal of the American Medical Association, 288, Schuster, M. A., Stein, B. D., Jaycox, L. H., Collins, R. L., Marshall, G. N., Elliott, M. N., et al. (2001). A national survey of stress reactions after the September 11, 2001, terrorist attacks. The New England Journal of Medicine, 345, Silver, R. C., Holman, E. A., McIntosh, D. N., Poulin, M., & Gil-Rivas, V. (2002). Nationwide longitudinal study of psychological responses to September 11. Journal of the American Medical Association, 288, Stein, B. D., Elliott, M. N., Jaycox, L. H., Collins, R. L., Berry, S. H., Klein, D. J., et al. (2004). A national longitudinal study of the psychological consequences of the September 11, 2001 terrorist attacks: Reactions, impairment, and help-seeking. Psychiatry, 67, Brief Treatment and Crisis Intervention / 6:2 May