Psychiatry 77(4) Winter 2014

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Older Adults Following Hurricane Sandy Shrira et al.

Previous Exposure to the World Trade Center Terrorist Attack and Posttraumatic Symptoms Among Older Adults Following Hurricane Sandy Amit Shrira, Yuval Palgi, Yaira Hamama-Raz, Robin Goodwin, and Menachem Ben-Ezra Objective: The present study tested the maturation and inoculation hypotheses by examining whether age and previous exposure to the September 11, 2001, World Trade Center (WTC) terrorist attack moderated the relationship between degree of exposure to Hurricane Sandy and related posttraumatic stress disorder (PTSD) symptoms. Method: An online sample of 1,000 participants from affected states completed self-report questionnaires one month after Hurricane Sandy hit the East Coast. Participants reported their degree of exposure to the WTC terrorist attack and to Hurricane Sandy, and their posttraumatic stress disorder (PTSD) symptoms following Hurricane Sandy. Results: The positive relationship between degree of exposure to Hurricane Sandy and level of PTSD symptoms was weaker among older adults. An additional significant three-way interaction suggested that both age and previous exposure to the WTC terrorist attack moderated the relationship between degree of exposure to Hurricane Sandy and level of PTSD symptoms. Previous high degree of exposure to the WTC terrorist attack was related to a weaker effect of current exposure to Hurricane Sandy on PTSD symptoms among older adults. However, among younger adults, previous high degree of exposure to the WTC terrorist attack was related to a stronger effect of current exposure on PTSD symptoms. Conclusions: When confronted by a natural disaster, American older adults are generally resilient. Supporting the inoculation hypothesis, resilience of older adults may be partly related to the strength successfully extracted from previous exposure to adverse events. Disasters, or collectively experienced traumatic events, may have a wide range of adverse consequences on mental and physical functioning (Galea, Nandi, & Vlahov, 2005; Neria, Nandi, & Galea, 2008). Older adults may be at greater risk to these adverse consequences, due to poorer physical, social, and financial resources (Knight, Gatz, Heller, & Amit Shrira, PhD, is affiliated with the Interdisciplinary Department of Social Sciences, Faculty of Social Sciences, at Bar-Ilan University in Ramat-Gan, Israel. Yuval Palgi, PhD, is with the Department of Gerontology, Faculty of Social Welfare and Health Sciences, at the University of Haifa in Haifa, Israel. Yaira Hamama-Raz, PhD, and Menachem Ben-Ezra, PhD, are with the School of Social Work at Ariel University in Ariel, Israel. Robin Goodwin, PhD, is with the College of Health and Life Sciences at Brunel University, London. From January 2015 he will be with the Department of Psychology, University of Warwick, UK. Address correspondence to Amit Shrira, Interdisciplinary Department of Social Sciences, Faculty of Social Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel. E-mail: [email protected] © 2014 Washington School of Psychiatry

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Bengtson, 2000). However, many studies found that compared to younger counterparts, older adults report similar or even lower level of distress following both natural and human-made disasters (Böttche, Kuwett, & Knaevelsrud, 2012; Norris, Friedman, Watson, Byrne, Diaz, & Kaniasty, 2002). For example, older age was related to lower psychological distress among hurricane survivors (Acierno, Ruggiero, Kilpatrick, Resnick, & Galea, 2006), as well as among combat veterans (Lunney, Schnurr, & Cook, 2014). Two major hypotheses try to explain the resilience (i.e., lower distress levels) of older adults (Knight et al., 2000). The maturation hypothesis assumes that post-disaster resilience among older adults is due to increased quality of coping style and regulation that comes with aging (Aldwin, Skinner, Zimmer-Gembeck, & Taylor, 2010; Diehl et al., 2014). For example, Diehl and colleagues (2014) found that increased age was related to more adaptive and less maladaptive coping and defense strategies. Even though this tendency began to reverse in late old age, the coping and defense strategies of the oldest individuals were still more adaptive than those of the youngest ones. The inoculation hypothesis argues that older adults are resilient to adverse events because of their greater experience with successful coping with prior negative life events (Eysenck, 1983). There is some overlap between the two hypotheses. Under some circumstances, the inoculation hypothesis can be viewed as a more specific case of maturation; for example, when resilience to current adversity is greater among older adults than among young adults and this pattern is especially salient among those with previous exposure. However, the two hypotheses differ from each other, as prior exposure to adversity is a necessary condition to late-life resilience according to the inoculation hypothesis, but not according to the maturation hypothesis.

The present study aimed to test both the maturation and inoculation hypotheses by focusing on previous exposure to the September 11, 2001, World Trade Center (WTC) terrorists attack and older adults’ resilience (i.e., lower posttraumatic distress) to current exposure to Hurricane Sandy (October, 2012). There are several reasons why reaction to Hurricane Sandy may be moderated by previous exposure to the WTC terrorists attack. First, Hurricane Sandy caused large devastation in lower Manhattan and also led to the shutdown of U.S. stock markets—all reminiscent of the effects brought about by the WTC terrorists attack. Moreover, Hurricane Sandy caused damage to the 9/11 Memorial and Museum, and the two disasters were frequently mentioned together by the media (e.g., a search for “9/11” and “Hurricane Sandy” in the New York Times online archive identified 186 results published in 2013). Therefore, Hurricane Sandy could have precipitated memories of the WTC terrorist attack that further affected stress reactions. Before returning to discuss the maturation and inoculation hypotheses, we briefly review evidence regarding the effects of the WTC terrorist attack and of natural disasters, focusing on older adults. Studies conducted following the WTC terrorist attack found older adults to report the same or lower level of distress compared to younger adults. Shortly after the attack, age was either unrelated (Schuster et al., 2001; Silver, Holman, McIntosh, Poulin, & Gil-Rivas, 2002; Tracy & Galea, 2006) or negatively related to PTSD symptoms (Schlenger et al., 2002). Approximately at the same period, Ford, Adams, and Dailey (2007) found that older adults around New York reported fewer days with mental health problems than did younger adults. In a more recent longitudinal study, older age was associated with lower overall levels of general distress and, most interestingly, with a steeper decline in PTSD symptoms over time (Scott, Poulin, & Silver,

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2013). To sum up, there are some indications that older adults showed greater resilience following the WTC terrorist attack, possibly inoculating them against future adversity. There is also abundant evidence suggesting that age is mostly negatively related to PTSD symptoms after various natural disasters (Acierno et al., 2006; Knight et al., 2000). Norris and colleagues (2002) found that in 15 out of 17 reviewed samples older persons were more resilient than younger persons, as evidenced by lower level of posttraumatic symptoms and other mental health problems. Norris and colleagues (2002) emphasized that the effect of age depends upon social, cultural, and historical contexts, but still in every American sample they examined older adults were less adversely affected than younger respondents. Therefore, the evidence gathered on various natural disasters, especially in the United States, largely suggests an inverse relationship between age and distress. However, as indicated above, the greater resilience presented by older adults faced with natural disasters may reflect either maturation or inoculation. Little previous research has directly tested the maturation and inoculation hypotheses in the context of old age. Knight and colleagues (2000) found lower distress among older adults before and after an earthquake. However, they did not find that post-earthquake distress was a product of the interaction between degree of exposure and age, and therefore concluded that there was no support for greater maturity of older adults confronted by a disaster. Others found inoculation among older adults who had experience with previous disasters. For example, in a sample of older adults interviewed before and after serious flooding, after controlling for pre-flood symptoms, there were modest flood effects on anxiety in those without prior flood experience but no flood effects in those who had been in a flood before (Phifer & Norris, 1989). Knight and colleagues (2000) also found that prior earthquake experience was related to lower post-earthquake depression among older

Older Adults Following Hurricane Sandy

adults. Norris and Murrell (1988) further found that the relationship between current exposure and distress decreased even if previous exposure included events that were not necessarily similar to the current event. Based on the above literature, there seems to be a need for further examination of maturation and inoculation among older adults. We therefore formulated two main hypotheses based on level of exposure to the WTC terrorist attack and Hurricane Sandy. According to Hypothesis 1, which tests the maturation hypothesis, there would be a weaker relationship between exposure to Hurricane Sandy and PTSD symptoms among older adults—regardless of their exposure to the WTC terrorist attack. According to Hypothesis 2, which examines the inoculation hypothesis, older adults would show less distress following exposure only if they report higher level of exposure to the WTC terrorist attack. To reiterate, if Hypothesis 1 would be confirmed but Hypothesis 2 would not, the maturation hypothesis would be corroborated. If Hypothesis 2 would be confirmed, the inoculation hypothesis would be corroborated. METHOD

Participants and Procedure Following approval by the Institutional Review Board of the School of Social Work at Ariel University, we used an online survey sample of 1,000 participants (response rate = 83.3% out of a potential 1,200), aged 18 or older, who were drawn from affected states (Connecticut, Maine, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, and Vermont) by Toluna (http://www.toluna-group.com), an Internet panel company. The survey was conducted during the fourth week of November 2012, one month after Hurricane Sandy struck the eastern coast of the United States. Internet panels are

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increasingly used as a viable means of data collection (Butt, Peipert, Webster, Chen, & Cella, 2013; Salsman et al., 2014). To recruit the study participants, Toluna sent e-mails to invite potential participants from a nonprobability-based panel to enroll in the current study if they upheld the following criteria: being age 18 or above, living in affected states, and speaking English. Participants’ mean age was 45.16 (SD = 14.29, range 18– 82), and the majority were women (n = 655; 65.5%), White (n = 846; 84.6 %), and married (n = 606; 60.6%). Almost half had college or higher education (n = 455; 45.5%). Measures Exposure was assessed with several items specifically constructed for the current study. Exposure to Hurricane Sandy was assessed using four items (losing property or belongings, home damaged, home destroyed, and witnessing an injury related to Hurricane Sandy). Exposure to the WTC terrorist attack was assessed using four items (being in Manhattan during 9/11, being in the vicinity of Ground Zero during 9/11, knowing people who were injured, or knowing people who were killed in the WTC terrorist attack). Items were rated as Yes or No, and answers summed (for each event, the possible range was 0 to 4). The summation index for Hurricane Sandy was also in line with previous study on inoculation following natural disaster (Knight et al., 2000). Summation index was also preferred over a dichotomized one for exposure to the WTC terrorist attack because it was a national trauma that affected individuals at various levels of exposure (including watching live media coverage, cf. Marshall et al., 2007). Posttraumatic stress disorder (PTSD) symptoms in the last month were assessed in reference to Hurricane Sandy by the Impact of Event Scale Revised (IES-R), a 22-item scale including domains of intrusion, avoidance/numbing, and hyperarousal (Weiss & Marmar, 1997). Participants answered to

what degree they were bothered by specific symptoms on a scale ranging from 0 (not at all) to 4 (extremely). Intensity of symptoms was summed across items to produce the final score (possible range = 0–88). The IES-R has high internal reliability and shows satisfactory test-retest stability and strong validity (Weiss, 2004). It was previously used following large-scale disasters (Ben-Ezra, Palgi, Soffer, & Shrira, 2012; Ben-Ezra & Soffer, 2010). Cronbach’s α in the current study was 0.97. Covariates included sociodemographic characteristics (gender, race/ethnicity, education and marital status) and self-rated health using a single-item (“How do you rate your health?”), ranging from 1 (poor) to 4 (excellent) (Idler & Benyamini, 1997). These variables were used as covariates, as some of them were related with age (there was a higher ratio of unmarried white women as age increased), and all are known correlates of post-disaster distress (Norris et al., 2002). Data Analysis In order to test the study hypotheses, we performed a hierarchical multiple regression. All continuous variables (age, exposure to Hurricane Sandy, exposure to the WTC terrorist attack, and self-rated health) were mean-centered. Covariates were entered in Step 1 and the various predictors entered in subsequent steps. In order to test both hypotheses, PTSD symptoms were regressed on the main effects of exposure to Hurricane Sandy, exposure to the WTC terrorist attack, and age in Step 2, and the interaction between exposure to Hurricane Sandy and age in Step 3. Following this, the two other possible two-way interactions between the three variables—exposure to Hurricane Sandy, exposure to the WTC terrorist attack, and age—were added in Step 4. Finally, the three-way interaction between the three variables was added in Step 5. Hypothesis 1 would be supported if there would be a significant two-way inter-

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TABLE 1. Number of Respondents Reporting Various Types of Exposure During the WTC Terrorist Attack and Hurricane Sandy %

n Exposure to the WTC terrorist attack Being in Manhattan during 9/11

276

27.8

Being in Ground Zero vicinity during 9/11

226

22.7

Know people who were injured

329

33.3

Know people who were killed

341

34.5

Exposure to Hurricane Sandy Lost personal property or belongings

184

18.7

Home was damaged

212

21.6

Home was destroyed

119

12.0

Witnessed an injury

146

14.8

Note. n = 1000. WTC = World Trade Center.

action between exposure to Hurricane Sandy and age, and a non-significant three-way interaction between exposure to Hurricane Sandy, exposure to the WTC terrorist attack, and age. Moreover, the two-way interaction should show that the relationship between exposure to Hurricane Sandy and PTSD symptoms was weaker among older adults compared to younger adults. Hypothesis 2 would be supported if the three-way interaction between exposure to Hurricane Sandy, exposure to the WTC terrorist attack, and age would be significant. Moreover, the three-way interaction should show that the weaker effect of exposure to Hurricane Sandy found among older adults would be restricted to those with high level of exposure to the WTC terrorist attack. Significant interactions were probed and plotted using the PROCESS computational tool (Hayes, 2013). This tool not only enables examination of the significance of slopes at different levels of the moderator (i.e., age), but also assesses the “regions of significance” for each effect using the Johnson-Neyman technique (Bauer & Curran, 2005; Hayes & Matthes, 2009)—meaning, it locates the values within the range of the moderator (i.e., age) in which exposure to Hurricane Sandy has a significant main effect on PTSD symptoms, or in which it significantly interacts with exposure to the WTC

terrorist attack to affect PTSD symptoms. As age remained a continuous variable, regression lines were plotted for those who are one standard deviation above and below the mean (titled older adults and young adults, respectively). As exposure to the WTC terrorist attack was also continuous, regression lines were also plotted for those who are one standard deviation above and below the mean. Using G*Power 3.1 (Faul, Erdfelder, Buchner, & Lang, 2009), we performed a sensitivity analysis for a regression coefficient embedded within multiple linear regression set to an effect size of ΔR2 = 0.01 with power = 0.80, and a two-tailed test. This effect size was based on interactions found in previous studies that are similar to the current study (e.g., Norris & Murrell, 1988). This analysis yielded a sample size of 779. Therefore, our sample of 1,000 was more than sufficient in order to detect such effects. RESULTS

Table 1 presents the number of respondents who reported each of the exposure type. More than half of the respondents (55.3%), and almost a third (29.9%) reported one or more type of exposure to the WTC

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TABLE 2. Means, Standard Deviations, and Intercorrelations Between the Study’s Variables M/%

SD

Range

1

1. PTSD symptoms

18.54

20.26

0–88

—

2. Exposure Sandy

0.66

1.21

0–4

.26**

2

3

4

—

3. Exposure WTC

1.17

1.32

0–4

.23**

.55**

—

4. Age

45.16

14.29

18-82

–.13**

–.11**

-.01

—

5. Sex (women)

65.5%

—

—

.02

.05

.05

.18** –.22**

6. Race/ethnicity (non-White)

15.4%

—

—

.09*

.06

.09*

7. Education level (college degree and above)

45.9%

—

—

–.01

.07*

.08*

.01

8. Marital status (married)

60.6%

—

—

.02

–.02

–.00

–.16**

2.81

0.74

1–4

–.05

–.01

–.05

.01

9. Self-rated health

Note. Maximal n = 1000. WTC = World Trade Center. Correlation values represent Pearson coefficients except for coefficients for sex, race/ethnicity, education level, and marital status that represent point-biserial coefficients. *p < .01. **p < .001.

terrorist attack and to Hurricane Sandy, respectively. Table 2 presents means, standard deviations, and intercorrelations between the study’s variables. PTSD symptoms were positively related to both degree of exposure to Hurricane Sandy and to the WTC terrorist attack. Age was negatively related to PTSD symptoms and to degree of exposure to Hurricane Sandy. Table 3 presents the regression findings testing our hypotheses. When PTSD symptoms were regressed on age, exposure to Hurricane Sandy, and exposure to the WTC terrorist attack (controlling for covariates), all three main effects were significant. Whereas age was negatively related to PTSD symptoms, both types of exposure were positively related to PTSD symptoms. Moreover, the Exposure to Hurricane Sandy × Age interaction was significant (B = -0.07, p = .025). Probing the interaction using PROCESS showed that the coefficient of exposure to Hurricane Sandy was B = 5.00, p < .00001, among younger adults (those 1 SD below the mean age) and B = 2.95, p = .0002, among older adults (those 1 SD above the mean age). Therefore, relative to younger adults, the relationship between degree of exposure to Hurricane Sandy and PTSD symptoms decreased among older adults.

The other two-way interactions (between exposure to the WTC terrorist attack and age, and between both types of exposures) were not significant. Finally, there was a significant three-way interaction between age and both types of exposure (B = –0.37, p = .017). Figure 1 presents the Exposure to Hurricane Sandy × Exposure to the WTC terrorist attack × Age interaction. As can be seen, when exposure to the WTC terrorist attack was high rather than low, the positive relationship between exposure to Hurricane Sandy and PTSD symptoms decreased among older adults (Figure 1(b)), but increased among younger adults (Figure 1(a)). In other words, high degree of previous exposure was related to a weaker effect of current exposure on PTSD symptoms among older adults. However, high degree of previous exposure was related to a stronger effect of current exposure on PTSD symptoms among younger adults. Taken together these findings corroborate the inoculation hypothesis for older adults: Weaker positive relationship between exposure and distress observed among older adults was restricted to those with high level of previous exposure. A similar pattern of resilience in older adults was not observed when examining those with low level of previous exposure. Indeed, when level of previous exposure to the WTC terrorist at-

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TABLE 3. Posttraumatic Stress Disorder Symptoms Predicted by Exposure to Hurricane Sandy, Exposure to the WTC Terrorist Attack, Age, and Their Interactions Variable

B

β

p

1.18

0.02

0.383

Step 1: Covariates (∆R2 = .012) Sex (women) Race/ethnicity (non-White)

5.14

0.09

0.005

Education (college degree and above)

–0.26

–0.00

0.842

Marital status (married)

0.04

0.00

0.975

Self-rated health

–1.41

–0.05

0.104

Age

–0.13

–0.09

0.003

Exposure Sandy

10.62

0.24

0.000

Exposure WTC

5.85

0.14

0.000

–0.07

–0.06

0.025

Exposure WTC × Age

0.01

0.01

0.870

Exposure Sandy × Exposure WTC

0.04

0.00

0.924

–0.61

0.017

Step 2: Main effects (∆R2 = .114)

Step 3: Focal two-way interaction (∆R = .004) 2

Exposure Sandy × Age Step 4: Other two-way interactions (∆R2 = .000)

Step 5: Three-way interaction (∆R2 = .006) Exposure Sandy × Exposure WTC × Age R2

–0.37

0.138

Note. n = 987. WTC = World Trade Center.

tack was low, it was the younger cohort that showed a weaker positive relationship between current exposure to Hurricane Sandy and PTSD symptoms. This last pattern could not be accommodated by the maturation hypothesis (see Discussion, below). An additional probe of the three-way interaction using the Johnson-Neyman technique (Bauer & Curran, 2005; Hayes & Matthes, 2009) showed that the interaction between both types of exposure was significant below age 24.6 and above age 59.5. Moreover, the interaction coefficients among the youngest ages were positive whereas they were negative among the oldest ages. This means that previous exposure increased the positive relationship between exposure to Hurricane Sandy and PTSD symptoms among the youngest respondents while among the oldest ones, previous exposure decreased the positive relationship between exposure to Hurricane Sandy and PTSD symptoms.

DISCUSSION

The current study aimed to examine the maturation and inoculation hypotheses among older adults while focusing on responses to Hurricane Sandy. In line with Hypothesis 1, the relationship between exposure to Hurricane Sandy and PTSD symptoms was weaker among older adults. However, in support of the inoculation hypothesis (Hypothesis 2), the age-related moderation effect was restricted to cases of prior exposure or, more specifically, to those with high degree of exposure to the WTC terrorist attack. We now turn to discuss our results in more detail. The weaker association between degree of exposure and PTSD symptoms found among older adults is consistent with previous evidence suggesting an inverse relationship between age and post-disaster psychopathology (Norris et al., 2002). It is not

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(a) Young adults (Age –1 SD below the mean)

(b) Older adults (Age +1 SD above the mean)

FIGURE 1. The Three-Way Interaction Between Exposure to Hurricane Sandy, Exposure to the WTC (World Trade Center) Terrorist Attack, and Age When Predicting PTSD Symptoms.

uncommon for people to gain experience, maturity, and wisdom that enhance adaptive coping abilities (Aldwin et al., 2010; Diehl et al., 2014) and improve emotional regulation (Urry & Gross, 2010) as they age. Previous exposure to the WTC terrorist attack emerged as an additional important factor which moderated the age-related effect seen following Hurricane Sandy. As reported, the weaker relationship between degree of exposure to Hurricane Sandy and PTSD symptoms observed among older adults was restricted to those previously exposed to high level of exposure to the WTC terrorist attack. This finding adds to existing evidence (Knight et al., 2000; Phifer & Norris, 1989) showing that inoculation is not limited to cases in which stressors from the same type follow each other, but that coping with disaster of one type (i.e., human-made) can also engender inoculation to a disaster of another type (i.e., natural). Notably, among young adults, previous exposure to the WTC terrorist attack produced a “kindling effect” (cf., Schumm, Stines, Hobfoll, & Jackson, 2005), as it strengthened the relationship between exposure to Hurricane Sandy and PTSD symptoms. It is possible that a kindling effect is more probable in young age, when people still lack life experience. Therefore, future studies should examine whether inoculation and kindling may depend on the timing of exposure and subsequent exposure.

It is important to note that we do not propose that effective coping strategies exist among all older adults. We do suggest, however, that on average, relative to young adults, older adults do possess more successful coping strategies (Diehl et al., 2014). According to the inoculation hypothesis, this age-related increase in adaptive coping is gradually produced by accumulated experience and knowledge on how to handle adverse situations. Still, one should also consider the variance in response to disaster, and that under certain circumstances, previous exposure loses its protective effect or even precipitates a negative effect. For example, Norris and Murrell (1988) proposed that prior exposure can protect from mental distress due to acute stressor, but loses its effect when current exposure is extended or constant. Moreover, previous exposure can sometimes overpower one’s abilities (Acierno et al., 2006), for example, when it is very severe or when the individual’s initial resources are low. The person then confronts additional adversity with fewer resources, and the threshold for tolerating more stress becomes lower. It is probable that inoculation and vulnerability depend on the results of previous coping rather than on previous exposure per se. This study focused on posttraumatic distress and resilience, assuming that higher distress reflects maladaptive coping mechanisms while resilience (i.e., lower posttraumatic distress)

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reflects adaptive coping mechanisms. Still, a more complete examination of the inoculation hypotheses should directly address coping mechanisms, testing whether inoculation among older adults is indeed related to prior successful coping. In any case, the current findings add to previous evidence (Knight et al., 2000; Norris & Murrell, 1988; Phifer & Norris, 1989) to suggest that inoculation seems to characterize the average response to disaster among older adults. Another point that should be emphasized is that although under specific circumstances, both maturation and inoculation hypotheses may be supported to some extent, the results of the current study mainly support the latter hypothesis. Indeed, the three-way interaction showed that among those with low level of exposure to the WTC terrorist attack, current exposure to Hurricane Sandy was associated with PTSD symptoms more strongly among older adults than among younger adults. This means that with little previous exposure, older adults were less resilient than younger adults, a finding that is not accommodated by the maturation hypothesis. The current findings should be assessed in view of the study limitations. First, our report was based on web-enabled research with an oversampling of women, whites, and well-educated individuals. The use of a web-based method also limited the age range in this study, and most of our older adults were middle-aged persons, with few sexagenarians, septuagenarians, and octogenarians (176 respondents were age 60 or above). Although web-based methods prove to be valuable when examining large samples shortly after disasters (Schlenger & Silver, 2006), they decrease the opportunity to study minorities, those with low-income, or older individuals who do not have easy access to the Internet. Such groups may be less able to cope adaptively. For example, physically disabled and frail old people were at high risk of developing mental distress following natural disaster (Gignac, Cott, & Badley, 1998).

Older Adults Following Hurricane Sandy

Moreover, as this study was more interested in the range of PTSD symptoms rather than in the prevalence of clinical disorders, PTSD symptoms were self-reported. Examining symptoms one month after the hurricane may have posed another problem, in that many affected potential participants may not have been sampled due to lack of resources secondary to hurricane damage loss. The use of cross-sectional data and the lack of pre-disaster measures were additional limitations. Finally, previous exposure to hurricanes or to other potentially traumatic events was not examined. Indeed, our respondents might have been exposed to additional stressors (including previous natural disasters). Nevertheless, as we preferred the use of a brief online survey, we chose to focus on exposure to the WTC terrorist attack because it was an unprecedented large-scale disaster with effects that would reverberate in many other circumstances—eliciting a sense of threat, particularly on the national level— such as Hurricane Sandy. Finally, as our study focused on Americans, there is a need to assess maturation and inoculation while accounting for diverse social, cultural, and historical contexts (Norris et al., 2002). Although American older adults consistently show lower distress, findings from other countries are mixed. For example, Norris, Kaniasty, Conrad, Inman, and Murphy (2002) showed that compared to other age groups, the oldest are less distressed in a Mexican sample, but most distressed in a Polish sample. In addition, less distress was found among older Japanese following an earthquake (Kato, Asukai, Miyake, Minakawa, & Nishiyama, 1996). Future studies should examine how different contexts moderate age effect following disaster, and examine whether cultural differences reflect different social policies and resources available to older people in various countries. The above limitations are balanced by several methodological strengths. First, findings were obtained from a large communitybased sample with an adequate sample size

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for statistical analysis. Moreover, to our knowledge, this is one of the few studies directly examining maturation and inoculation among older adults. To conclude, older adults confronted by Hurricane Sandy were found to be generally resilient or, more specifically, were found to report lower levels of PTSD symptoms. This resilience was primarily manifested by those who reported high degree of exposure to the WTC terrorist attack. In support of the inoculation hypothesis, it is proposed that prior exposure is an important factor

that promotes greater coping and regulation abilities with age. Clinicians working with older adults need to be aware of prior exposure, and of its potential inoculating effect. Moreover, adaptive coping following disasters (Hobfoll et al., 2007) can be promoted by using the experience of previously exposed older adults. Experienced resilient older adults can help and comfort others, while they themselves can be encouraged to feel greater competence and self-esteem in their role as helpers in times of distress.

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