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Post-traumatic stress disorder and depression among adult survivors 8 years after the 2008 Wenchuan earthquake in China
Journal of Affective Disorders 210 (2017) 27–34
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Research paper
Post-traumatic stress disorder and depression among adult survivors 8 years after the 2008 Wenchuan earthquake in China
MARK
⁎
Jing Guoa, , Huan Heb, Zhiyong Quc, Xiaohua Wangc, Chengbin Liua a b c
School of Sociology, Huazhong University of Science and Technology, Wuhan 430074, PR China Department of Public Administration, Southwestern University of Finance and Economics, Chengdou 610074, PR China School of Social Development and Public Policy, China Institute of Health, Beijing Normal University, Beijing 100875, PR China
A R T I C L E I N F O
A BS T RAC T
Keywords: PTSD Depression Earthquake
Background: The Wenchuan earthquake was China's worst natural disaster of the past three decades. Although the psychological sequelae of disasters can last for many years, the long-term sequelae and their risk factors tend to receive little research attention. Objectives: The objectives of the present study were to estimate the prevalences of symptomalogical PTSD and depression among survivors 8 years after the Wenchuan earthquake, and to identify the shared and unshared risk factors associated with PTSD and depression, using data from a cross-sectional survey. Methods: 1369 participants were recruited from two different sites in the areas that were severely affected by the earthquake. Symptomalogical PTSD was assessed by the Impact of Event Scale-Revised (IES-R). The Chinese edition of the Center for Epidemiologic Studies Depression Scale (CES-D) was used to assess depression. Traumatic exposure to the Wenchuan earthquake was assessed using an exposure checklist designed by this study. Results: Eight years after the Wenchuan earthquake, 11.8% of the respondents had symptomalogical PTSD, and 24.8% of respondents had probable depression. The results also indicated that female gender, low education, poor perceived health, and traumatic experiences after the earthquake were associated with higher odds of both PTSD and depression among survivors. Direct exposure to the earthquake was associated with comorbid symptomalogical PTSD and depression (OR=1.86; 95% CI=1.42, 2.44). Those having only depression were more likely to be unmarried/divorced/widowed, and to have experienced fear at the time of the earthquake (OR=1.34; 95% CI=1.04, 1.72), while those with only symptomalogical PTSD were likely to be from the township of Yongan as opposed to Guangji (OR=1.86; 95% CI=1.06, 3.31). Limitations: This is a cross-sectional study, and thus is insufficient for determining causal relationships with regard to chronic PTSD or depression. Conclusions: The results of this study indicate that symptomalogical PTSD and depression persist among many survivors of the Wenchuan earthquake, 8 eight years later. Objective earthquake exposure is associated with symptomalogical PTSD, while subjective exposure is associated with long-term depression.
1. Introduction Globally, people in less developed countries and regions are more likely to be affected by natural disasters, and a huge number of people die from all kinds of disasters in these countries (Wang et al., 2000). However, due to limited financial support and public attention, little post-disaster research is conducted in developing countries. China is an earthquake-prone country, and since 1950, half of the deaths that were caused by natural disasters in China were caused by earthquakes, which also caused great economic damage (Hou et al., 2016; Jin,
⁎
2014). PTSD and depression are the most common mental disorders following earthquakes. PTSD prevalence estimates vary widely, with most being in the 20–40% range, in disaster-focused studies (Bromet et al., 2016). Recent reviews have suggested that nearly 1 in 4 earthquake survivors develop PTSD (Dai et al., 2016). Considering these facts, there is a need for more research on the mental health consequences of severe earthquakes in China. The Wenchuan earthquake was China's worst natural disaster of the past three decades. On May 12, 2008, a magnitude 8.0 earthquake struck the area around Wenchuan County, in the northwestern part of
Corresponding author. E-mail address: [email protected] (J. Guo).
http://dx.doi.org/10.1016/j.jad.2016.12.009 Received 17 August 2016; Received in revised form 22 October 2016; Accepted 12 December 2016 Available online 16 December 2016 0165-0327/ © 2016 Elsevier B.V. All rights reserved.
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conducted among survivors of the 2008 Wenchuan earthquake in February 2016, eight years later. Participants were recruited from two different sites in the area that was severely affected by the earthquake. The first survey site was the township of Yongan (115.7 km from the epicenter) in Beichuan County, which is located in a mountainous area. Over 90% of the buildings in Yongan were damaged in the earthquake. The earthquake killed 15,645 people and left 26,916 people injured, and 1023 missing in Beichuan County. The second site was the township of Guangji (58.3 km from the epicenter) in Mianzhu County, which is located on a plain. Over 96% of the buildings in Guangji were damaged in the earthquake. It has been confirmed that 11,098 people were killed, 36,468 people were injured, and 298 people missing in Mianzhu County. These two townships were selected because both are close to the epicenter but at somewhat different distances, both suffered severe destruction in the earthquake, and both had similar socioeconomic and demographic characteristics before the earthquake. This cross-sectional study used a combined multistage systematic sampling and convenience sampling design to select participants. In the first stage, 12 of the total 29 villages were randomly selected from the two survey townships. In the second stage, households, rather than individuals, were systematically selected, using village registration information, as the basic unit for the entire survey. But in a small number of villages, many former residents were no longer residing in their homes, making such systematic sampling unfeasible; in these villages, non-random sampling methods were therefore also used. Adults over age 16 in each household were selected for participation. The actual samples achieved amounted to a total of 1369 adults. A higher than 90% response rate was achieved. These samples were representative of two townships that were severely affected by the Wenchuan earthquake. Face-to-face interviews were conducted, in Mandarin Chinese and in the local dialects and languages, by 22 college students from Mainyang Normal University. All of the interviewers were thoroughly trained before the survey. The training involved the following five sessions: introduction, sampling design and procedures, review of the questionnaire, methods and techniques of interviewing, and potential difficulties in conducting the survey. The interviewers were required to show their identification and explain the aims of the study prior to requesting permission to enter the participants' houses. They read each question out to the respondents, and then wrote down their answers on the questionnaire. The average interview time was 1 h. The study protocol was approved by the Institutional Review Board of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. All participants gave consent after being informed about the aim of the survey and their right to refuse to participate.
Sichuan province. It left 69,227 people dead, 374,643 injured, 17,923 missing, and millions homeless (SCIOC, 2008). Large studies showed that PTSD was the most prevalent mental disorder among survivors of the Wenchuan earthquake (Hong and Efferth, 2015). Kun et al. (2009) reported that the prevalence of probable Post-traumatic Stress Disorder (PTSD) was 45.5% in the heavily damaged Beichuan County two and half months after the earthquake. Studies of the impact of the Wenchuan earthquake on the mental health of its survivors found that female gender, older age, lower household income, ethnic minority status, low educational level, living in a shelter or temporary house, death or a bodily injury in one's family, and household damage, were important risk factors associated with PTSD among adults (Kun et al., 2009; Wang et al., 2009; Zhang and Ho, 2011; Zhang et al., 2011). Disaster-related psychological sequelae can last for many years, but the long term sequelae and their risk factors tend to receive little research attention. A recent systematic review found that the number of journal articles published on the health consequences of an earthquake tend to drop dramatically 2 years after its occurrence (Xiao et al., 2011). To the best of our knowledge, very few studies to date have focused on the long term mental health effects of this disaster. Eight years have passed, and no existing study has examined the long term prevalences of mental disorders and related predictors among Chinese adult earthquake survivors. More research on the long-term psychiatric outcomes of the Wenchuan earthquake is needed. The following three factors are potential predictors of symptomalogical PTSD following an earthquake: traumatic experience(s) before the earthquake, traumatic exposure to the earthquake, and traumatic experience(s) after the earthquake (Cénat and Derivois, 2015). In previous studies, the term “direct exposure” referred to experiencing or witnessing the traumatic stressor, and “indirect exposure” was defined as learning about “death, serious harm, or threat of death or injury experienced by a family member or other close associate” (Zimering et al., 2006). Other studies have indicated that traumatic stress scores are associated with high subjective fear during exposure (Lonergan, 2014). In this study, we defined subjective exposure as fear at the time of the earthquake. Although many studies have found that direct and indirect exposure are highly associated with both depressive and Symptomalogical PTSD (Zimering et al., 2006), findings about the relationship of PTSD and depression to subjective exposure have been inconsistent. For example, one study suggested that impaired fear inhibition may be a specific biomarker of Symptomalogical PTSD (Jovanovic et al., 2010). Another study found during-disaster fear to be highly correlated with depression (Tang et al., 2014). The difference in findings may be due to differences in cultural context, study design, and/or sampling methods. In addition, some studies have compared the shared and unshared predictors of depressive and symptomalogical PTSD among adult earthquake survivors. One study found that being female, having a low income level and having a low perceived level of social support were all associated with both depression and PTSD (Wu et al., 2013). Another study found traumas such as loss of both parents and, to a lesser degree, loss of a father to be significant risk factors for depression, but not for PTSD, among adolescents (Goenjian et al., 2009). To what extent do these findings apply to survivors of the 2008 earthquake in China? The objectives of the present study were to estimate the prevalences of symptomalogical PTSD and depression among survivors 8 years after the Wenchuan earthquake, and to identify the shared and unshared risk factors associated with PTSD and depression, using data from a cross-sectional survey.
3. Measurement 3.1. Main outcome measures Probable Symptomalogical PTSD: symptomalogical PTSD was assessed by the Impact of Event Scale-Revised (IES-R) (Weiss and Marmar, 1997), a self-report instrument widely used in the field of traumatic stress. It includes 22 items used to measure the three major symptom clusters of PTSD: Intrusion, avoidance, and hyper-arousal. The IES-R's measures have been found to have good and stable psychometric properties (Creamer et al., 2003). The Chinese version of the IES-R has been found to have satisfactory psychometric properties, comparable to those of the original English version (Chen et al., 2007; Wu and Chan, 2003). In this study, the IES scale was used to investigate only posttraumatic symptoms related to the Wenchuan earthquake. The participants were asked to indicate the frequency of their distress using 4 response options (0=not at all, 1=seldom, 3=sometimes, 5=often) (Chan et al., 2012; Chan et al., 2011, 2012;
2. Methods 2.1. Study design and participants This study is based on a community-based, cross-sectional survey 28
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earthquake. Traumatic experience before the earthquake (Pre-quake trauma) was assessed using the yes/no question: “Did you experience any traumatic event before the earthquake? ” Traumatic experience after the earthquake (Post-quake trauma) was assessed using: “Did you experience any traumatic event after the Wenchuan earthquake? ” Demographic and socioeconomic variables: The following demographic and socioeconomic information was also collected in the survey: Township of residence (Yongan/Guangji); gender (female/ male); ethnicity (Han vs. Minority, with the latter including Qiang, Tibetan, Hui, Mongol and other minority groups); age (16–35 years/ 35–55 years/ > 55 years); marital status (married/unmarried/other status); educational level (primary school or below /middle school or above); self-reported household income (low/middle/high); self-reported perceived health (good/poor). These variables were included in the analyses because they have been examined in prior related studies (Kun et al., 2009; Wang et al., 2009; Zhang and Ho, 2011; Zhang et al., 2011).
Qu et al., 2012a; Qu et al., 2012a, 2012b). Subscale scores were calculated as the means of the responses to all of the items in the specific subscale, and the total score was calculated as the mean response across all items. Since there is no recommended cutoff point for the IES-R (Christianson and Marren, 2012), this study adopted a mean score of 2.0 across all items of the IES-R as the cutoff point, as was done in earlier studies (Chan et al., 2011; Guo et al., 2015; Qu et al., 2012a; Qu et al., 2012a, 2012b). One earlier study using this cutoff point reported a sensitivity of 0.89 and a specificity of 0.90 (Wohlfarth et al., 2003). The internal consistency coefficient (Cronbach's alpha) of the whole scale in the present study was 0.93. Depression: The Chinese edition of the Center for Epidemiologic Studies Depression Scale (CES-D) (Wang, 1999) was used to assess probable depression. This scale is the most widely used depressionscreening scale and has been used in many community-based studies. The Chinese version of the CES-D scale has shown good reliability and validity across all age groups in urban populations (Zhang et al., 2010). In our study, we used 21 as the cutoff point, as this has been shown to be a good predictor of depression in Chinese populations (Cheng and Chan, 2005). The internal consistency coefficient (Cronbach's alpha) of the whole scale in the present study was 0.88.
3.4. Statistical analysis SPSS 22.0 (SPSS Inc, Chicago, IL) was used for statistical analysis. Descriptive statistics were calculated for all of the socio-demographic and confounding variables. Univariate regression analysis was conducted to determine whether symptomalogical PTSD and depression were significantly associated with any of the socio-demographic variables and numbers of exposures. Binary logistic regression analysis was used to examine the effects of the risk factors on symptomalogical PTSD and depression. Then, the whole sample was divided into four groups: PTSD only, depression only, PTSD and depression, and No diagnosis. Multinomial logistic regression analysis was used to identify whether particular mental health status categories were associated with different groups of predictors. All p values were derived from adjusted Wald F tests based on these regression models. These analyses allowed us to meet the objectives outlined in the introduction to this paper.
3.2. Main measures of independent variables Traumatic exposure to the Wenchuan earthquake was assessed using an exposure checklist. We developed this measure, with the help of suggestions from five experts in the field, and some Wenchuan earthquake survivors. It has 12 items, covering three dimensions: direct exposure, indirect exposure, and subjective exposure. Direct exposure refers to respondents’ having been trapped or injured, or seen others thus exposed, during the earthquake. Indirect exposure refers to their family members, friends or being directly exposed to the earthquake. Subjective exposure refers to the participants’ having been afraid, during the earthquake, of being trapped, injured, or killed. The participants were asked to answer “yes” or “no” regarding each kind of exposure (See Table 1).
4. Results 4.1. Descriptive analysis
3.3. Potential confounders The respondents to the survey were mainly female, married, and members of the Han ethnic group, which makes up most of the population of China. Also, because the surveyed townships were both located in a rural area, most of the participants were farm workers with relatively low levels of education. The median age of the participants was 56 years and their mean age was 54.34 years (SD=15.9).13.1% of the participants were religious, most of them being Buddhists. 28.1% of the participants considered their family incomes to be low. The overall prevalences of symptomalogical PTSD and depression were 11.8% and 24.8%, respectively. Rates of symptomalogical PTSD were significantly higher among those from Yongan, and among female, middle aged, married, less educated, and low income participants. In addition, rates of depression were significantly higher among religious, older, divorced/widowed, and less educated participants. Respondents who had experienced traumatic events before the quake were more than 1.59 times as likely to exhibit symptomalogical PTSD compared to those with no pre-quake traumatic experiences (95% CI=1.14, 2.21). Those who had experienced traumatic events after the earthquake (OR=1.93; 95% CI=1.32, 2.84) were more likely to exhibit symptomalogical PTSD than other respondents. In addition, those who had experienced traumatic events after the earthquake were 2.35 times more likely to have depression than those who had not. (95% CI=1.74, 3.16) (Table 2). As illustrated in Fig. 1, the prevalence of symptomalogical PTSD only was 5.3% at 8 years after the earthquake, while the prevalences of depression only, and of symptomalogical PTSD with depression, were 18.4% and 6.4% respectively. Females were more likely to have
Three factors that can affect the mental health of earthquake survivors include: traumatic experiences before the earthquake, traumatic exposure to the earthquake, and traumatic experiences after the Table 1 Exposures to the Wenchuan earthquake among adult survivors. Dimensions
Direct exposure
Indirect exposure
Subjective exposure
Items
1. Were you trapped? 2. Were you injured? 3. Did you see someone trapped? 4. Did you see someone die or be injured? 5. Did you have family members who were trapped? 6. Did you have family members who were injured? 7. Did you have family members who died? 8. Did you have relatives or friends who were trapped? 9. Did you have relatives or friends who were injured? 10. Did you have relatives or friends who died? 11. Did you fear being trapped, injured, or killed? 12. Did you fear that someone else would be trapped, injured, or killed?
Score 0
1
No No No No No
Yes Yes Yes Yes Yes
No
Yes
No No
Yes Yes
No
Yes
No
Yes
No
Yes
No
Yes
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Table 2 Sample characteristics and odds of PTSD and depression eight years after the Wenchuan earthquake in China. Total N (%)
PTSD N (%)
OR (95% CI)
Depression N (%)
OR (95% CI)
Total Location Guangji Yongan
1369 (100) 677 (49.5) 692 (50.5)
161 (11.8) 57 (8.4) 104 (15.0)
1 1.92 (1.37, 2.71)***
340 (24.8) 162 (23.9) 178 (25.7)
1 1.01 (0.86, 1.41)
Gender Male Female
632 (46.6) 725 (53.4)
49 (7.8) 107 (14.8)
1 2.06 (1.44, 2.94)***
123 (19.5) 212 (29.2)
1 1.71 (1.33, 2.20)**
Ethnicity Han Minority
1283 (94.6) 73 (5.4)
146 (11.4) 12 (16.4)
1 1.53 (0.81, 2.91)
317 (24.7) 18 (24.7)
1 0.99 (0.58, 1.72)
Religion No Yes
1181 (86.9) 178 (13.1)
137 (11.6) 23 (12.9)
1 1.13 (0.71, 1.81)
279 (23.6) 57 (32.0)
1 1.52 (1.08, 2.15)*
Age 16–35 35–55 > 55
151 (11.8) 484 (35.8) 644 (50.4)
9 (6.0) 64 (13.2) 70 (10.9)
1 2.40 (1.17,4.96)* 1.93 (0.94,3.05)
21 (13.9) 115 (23.8) 174 (27.0)
1 1.93 (1.16, 3.20)* 2.29 (1.40, 3.75)***
Marital status Unmarried/others Married
234 (17.4) 1109 (82.6)
16 (6.8) 142 (12.8)
1 2.00 (1.17,3.42)*
74 (31.6) 256 (23.1)
1 0.65 (0.48, 0.88)**
Education Middle/above Primary/below
414 (30.5) 942 (69.5)
26 (6.3) 133 (14.1)
1 2.45 (1.58, 3.80)***
57 (13.8) 276 (29.3)
1 2.60 (1.90, 3.55)***
Income Rich Middle Poor
115 (8.5) 861 (63.4) 381 (28.1)
7 (6.1) 87 (10.1) 64 (16.8)
1 1.73 (0.78, 3.84) 3.11 (1.39, 7.00)
26 (22.6) 163 (18.9) 150 (39.4)
1 0.80 (0.50, 1.28) 2.22 (1.37, 3.60)
Perceived health Good Poor
950 (69.6) 415 (30.4)
84 (8.8) 77 (18.6)
1 2.35 (1.68, 3.28)
186 (19.6) 153 (36.9)
1 2.40 (1.86, 3.10)
Pre-quake trauma No Yes
842 (61.5) 527 (38.5)
83 (9.9) 78 (14.8)
1 1.59 (1.14, 2.21)**
199 (23.6) 141 (26.8)
1 1.18 (0.92, 1.52)
Post-quake trauma No Yes
1117 (82.7) 233 (17.3)
117 (10.5) 43 (18.5)
1 1.93 (1.32, 2.84)***
243 (21.8) 92 (39.5)
1 2.35 (1.74, 3.16)***
Note: N, number; OR, odds ratio; 95% CI, confidence interval. *** P < 0.001. ** P < 0.01. * P < 0.05.
symptomalogical PTSD than males.
4.2. Regression analysis Table 3 presents the results of the multivariate logistic analysis assessing the risk factors for symptomalogical PTSD and depression. The independent variables included numbers of direct exposure, indirect exposure, and subjective exposure. Potentially confounding variables included in the model were socio-economic variables, perceived health, and traumatic experience before/after the earthquake. With these variables controlled for, post-quake traumatic experience was significantly associated with both depression and PTSD. However, direct exposure (OR=1.59; 95% CI=1.30, 1.96) was only significantly associated with probable PTSD. Having experienced high fear at the time of the earthquake was a significant risk factor for depression (OR=1.32; 95% CI=1.05, 1.66), but not for PTSD. Table 4 displays the results of the multi-nominal logistic regression analysis. As compared with participants with no diagnosis, those with
Fig. 1. Prevalence of PTSD and depression among adult survivors eight years after the Wenchuan earthquake (%).
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5. Discussion
Table 3 Logistic Regression results for risk factors of PTSD and depression among adult survivors eight years after the Wenchuan earthquake in China. PTSD
Direct exposure
a
b
Indirect exposure
Subjective exposurec
Town (Ref: Guangji) Yongan
OR (95% CI)
P-value
OR (95% CI)
P-value
1.59 (1.30, 1.96) 1.12 (0.98, 1.28) 1.08 (0.80, 1.46)
< 0.001
1.13 (0.95, 1.35) 1.02 (0.92, 1.14) 1.32 (1.05, 1.66)
0.173
0.110 0.615
0.685 0.016
1.57 (1.04, 2.35)
0.031
1.01 (0.75, 1.37)
0.933
1.80 (1.19, 2.73)
0.006
1.55 (1.15, 2.10)
0.004
1.10 (0.46, 2.64) 0.93 (0.37, 2.30)
0.832
1.38 (0.71, 2.69) 1.28 (0.66, 2.50)
0.336
0.91 (0.41, 2.01)
0.812
0.90 (0.46, 1.77)
0.758
0.62 (0.34, 1.15)
0.128
0.83 (0.54, 1.27)
0.382
Marital status (Ref: Unmarried/others) Married 2.26 (1.15, 4.46)
0.018
0.50 (0.34, 0.74)
0.001
Education (Ref: Middle school or above) Prim-school/below 2.15 (1.22, 3.80)
0.008
2.37 (1.56, 3.60)
< 0.001
2.28 (0.92, 5.69) 1.35 (0.56, 3.30)
0.077
1.57 (0.90, 2.76) 0.70 (0.41, 1.21)
0.114
1.82 (1.22, 2.74)
0.004
2.00 (1.48, 2.71)
< 0.001
1.10 (0.73, 1.64)
0.653
0.96 (0.71, 1.30)
0.781
1.81 (1.15, 2.86)
0.010
2.05 (1.44, 2.92)
< 0.001
Gender (Ref: Male) Female
Age (Ref: 16–35) 35–55 > 55
Ethnicity (Ref: Han) Minority
Religion (Ref: No) Yes
Income (Ref: High) Low Middle
Perceived health (Ref: Good) Poor
Pre-quake trauma (Ref: No) Yes
Post-quake trauma (Ref: No) Yes
Our study, conducted eight years after the Wenchuan earthquake, allowed us to learn more about the psychological sequelae associated with a large-scale disaster in a developing country. In this study, symptomalogical PTSD and depression were evaluated by valid measurement tools. Various levels of earthquake exposure were also assessed. Our results show that the prevalences of symptomalogical PTSD and depression remained high 8 years after the earthquake among the adult survivors. The findings reported here also suggest that direct and other types of earthquake exposure variables affected chronic symptomalogical PTSD and comorbid symptomalogical PTSD and depression, while high fear at the time of the earthquake only had a long-term effect on depression. These findings illustrate the importance of studying the prevalences and risk factors for PTSD and depression among earthquake survivors in developing countries. Firstly, the study found that the survivors had long-term psychiatric morbidity, even 8 years after the earthquake. Examination of the longterm prevalence of PTSD was lacking in prior studies. One study conducted among adult survivors 10–11 years after the 9/11 attacks found that 15.2% of respondents reported symptoms indicative of PTSD and 14.9% met criteria for depression; 10.1% experienced both (Caramanica et al., 2014). Our own prior study showed that 8.0% of earthquake survivors had PTSD symptoms 44 months after the Wenchuan earthquake (Guo et al., 2013). The present study found that the prevalence of symptomalogical PTSD was 11.8% eight years after the earthquake, while the prevalences of depression and comorbid PTSD and depression were 24.8% and 6.4% respectively. The PTSD prevalence found in this study is a little higher than our prior study. Such variability is maybe partially explained by changes in the nature of the sample. Because some young subjects migrated out of the area, looking for work, after the earthquake, the mean age of the current study's participants is older than in the previous study. But these results certainly show that PTSD rates did not decline in the area in the years after the first study was conducted, and depression was more common than PTSD among adult survivors 8 years after the Wenchuan earthquake. Researchers, health care professionals, and the public should be aware that affected individuals may continue to present earthquake-related trauma symptoms long after the event; ongoing surveillance and services are needed. Secondly, the findings indicate that female gender, low education, poor perceived health, and traumatic experience after the earthquake are associated with both PTSD and depression among survivors. This is consistent with prior studies. Research findings on the role of gender in the prediction of PTSD symptoms following earthquakes in adult populations have shown higher vulnerability in women (Dell'Osso et al., 2011). Explanations offered in prior studies suggest that women's higher risk of PTSD & depression may be due to their stronger perceptions of threat and loss of control, higher levels of peri traumatic dissociation, and gender-specific acute psychobiological reactions to trauma (Gavranidou and Rosner, 2003; Olff et al., 2007). Groups with low education and poor perceived health tend to have longer-lasting mental health problems. The reason maybe that these vulnerable groups lack the ability to recover from the disaster. Misfortunes never come singly. Survivors who experience another traumatic event again after an earthquake are more sensitive to the experience. This is why they are more likely to have persistent depressive and PTSD symptoms. The Wenchuan earthquake was the second most destructive earthquake to hit China to date, and the results of this study have implications for policy and planning. Health care providers, researchers, and government officials need to continue to address the mental health needs of vulnerable subgroups of those affected, such as female survivors and survivors with more types of disaster exposures. Thirdly, this study reveals there are differential constructs for PTSD and depression among adult survivors following the Wenchuan earthquake. The findings of studies on the risk factors for PTSD and
Depression
0.872
0.503
0.467
0.203
Note: a, b, c: Reference: numbers of exposure.
depression only were likely to be unmarried/divorced/widowed, and to have experienced high fear at the time of the earthquake (OR=1.34; 95% CI=1.04, 1.72), while those with symptomalogical PTSD only were likely to be from Yongan (OR=1.86; 95% CI=1.06, 3.31). Moreover, those with direct exposures to the earthquake (OR=1.86; 95% CI=1.42, 2.44) were more likely to have comorbid depression and PTSD. In addition, female gender and post-quake traumatic event were positively associated with each of the probable diagnoses of PTSD only, depression only, and PTSD with depression.
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Table 4 Results of multi-nominal logistic regression of risk factors for PTSD only, depression only, and PTSD with depression among adults eight years after the Wenchuan earthquake in China. Only Depression (N=252)
Only PTSD (N=73)
PTSD & Depression (N=88)
ORa (95% CI)
P-value
ORa (95% CI)
P-value
ORa (95% CI)
P-value
Direct exposure Indirect exposure Subjective exposure
0.93(0.74, 1.16) 1.02(0.90, 1.16) 1.34(1.04, 1.72)
0.500 0.755 0.022
1.28(0.95, 1.72) 1.17(0.98, 1.41) 1.05(0.71, 1.55)
0.104 0.088 0.809
1.86(1.42, 2.44) 1.09(0.90, 1.31) 1.30(0.83, 2.04)
< 0.001 0.384 0.258
Town (Ref: Guangji) Yongan
1.00(0.72, 1.39)
0.988
1.86(1.06, 3.28)
0.031
1.31(0.75, 2.30)
0.349
Gender (Ref: Male) Female
1.52 (1.09, 2.11)
0.013
1.87 (1.06, 3.31)
0.032
2.08 (1.16, 3.71)
0.014
Age (Ref: 16–35) 35–55 > 55
0.70 (0.34, 1.45) 1.11 (0.77, 1.59)
0.334 0.589
0.90 (0.28, 2.83) 1.32 (0.73, 2.39)
0.851 0.355
1.40 (0.34, 5.76) 1.16 (0.64, 2.09)
0.638 0.628
Ethnicity (Ref: Han) Minority
0.87 (0.39, 1.92)
0.731
0.87 (0.31, 2.46)
0.790
0.86 (0.28, 2.70)
0.800
Religion (Ref: No) Yes
0.85 (0.53, 1.37)
0.511
0.55 (0.21, 1.47)
0.234
0.58 (0.26, 1.26)
0.166
Marital status (Ref: Unmarried/others) Married 0.43 (0.29, 0.65)
< 0.001
2.30 (0.78, 6.80)
0.132
1.35 (0.57, 3.21)
0.492
Education (Ref: Middle school or above) Primary school/ below 2.01 (1.28, 3.14)
0.002
1.48 (0.75, 2.93)
0.258
5.83 (2.16, 15.74)
< 0.001
Income (Ref: Rich) Poor Middle
1.59 (0.85, 2.98) 0.84 (0.46, 1.52)
0.147 0.560
5.20 (0.66, 40.72) 5.34 (0.72, 39.78)
0.117 0.102
1.82 (0.65, 5.11) 0.49 (0.17, 1.38)
0.253 0.175
Perceived health (Ref: Good) Poor
1.84 (1.31, 2.58)
< 0.001
1.47 (0.82, 2.62)
0.196
3.03 (1.73, 5.31)
< 0.001
Pre-quake trauma (Ref: No) Yes
0.87 (0.62, 1.21)
0.405
0.88 (0.50, 1.55)
0.655
1.26 (0.72, 2.18)
0.422
Post-quake trauma (Ref: No) Yes
2.35 (1.59, 3.47)
< 0.001
2.69 (1.46, 4.94)
0.001
2.00 (1.06, 3.81)
0.034
Note: a Compared to “neither PTSD nor depression” cases (N=956).
require further study. Better understanding the similarities and differences between the risk factors for PTSD and depression will help in developing more targeted, specific interventions after the disasters. Finally, we developed an exposure checklist in this study. Many studies have used the concepts of direct and indirect exposure in assessing levels of exposure to disasters (Zoellner et al., 2014). We decided to use subjective perceived exposure as an exposure measure. In this study, we found that objective exposure is associated with chronic symptomalogical PTSD and its comorbidity with depression, while subjective perceived exposure is associated with long-term depression. This shows that objective and subjective exposure may have different effects on the psychological sequelae of disasters. Our checklist has twelve simple items. It can be used by social workers and public health workers to conduct rapid evaluation of individuals’ exposures to an earthquake. It should be noted that this tool needs further development and should be examined in further studies. The findings of this study contribute to extant knowledge on the long-term mental health consequences of natural disasters. The observed high prevalences of PTSD, depression, and comorbid PTSD and depression among these earthquake survivors demonstrate the need for continued mental health research, screening and treatment, especially among vulnerable groups in disaster-prone areas. Additionally, our findings indicate that PTSD and depression together constitute a general psychiatric response to trauma, and that the factors that predict PTSD are different from those that predict
depression have been inconsistent. O'Donnell et al. (2004) examined the factors predicting PTSD and depression among traumatic injury survivors, and found that similar sets of factors were predictive of each of these two conditions. However, Kaltman et al. (2010) conducted a study among Latina immigrants to the United States, and found that quite different sets of factors correlated with each of these two conditions. Our results are consistent with Kaltman's. We found that long-term depression was associated with high fear at the time of the earthquake, while chronic symptomalogical PTSD was associated with being from Yongan. Moreover, those with direct exposures to the earthquake were more likely to have comorbid depression and PTSD. This may be explained by a strong association between depression and subjective memories of fear, with PTSD being more associated with objective exposure. Compared to Guangji residents, Yongan residents were more likely to have chronic symptomalogical PTSD. Perhaps this has to do with Yongan's being located in a mountainous area, while Guangji residents live on flatter ground. Moreover, the results of the binary regression analysis indicated that unmarried/divorced/widowed people were more likely to have depression, while married people were more likely to have PTSD. A possible reason may be that marriage is a double-edged sword. Unmarried/divorced/widowed people lack support against negative emotions or depressive symptoms, but married people tend to be extremely worried about harm to their family members and possessions in a disaster (Wang et al., 2011). The specifics of the longitudinal relationship between PTSD and depression 32
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depression. This finding has potential clinical implications for improved treatment of these conditions, as comorbidity of PTSD and depression has been shown to have implications in terms of treatment efficacy and biological profile. To the authors' knowledge, this study is among the first investigations of the long-term mental health effects of an earthquake among survivors; it is also one of a handful of studies of the psychological sequelae of catastrophic natural disasters among populations not from Western countries. Besides these strengths, the present study has several limitations that should be mentioned. First, it is a cross-sectional study, and is thus insufficient for determining causal relationships with regard to chronic PTSD. Future studies, using longitudinal data, are needed to explore the risk factors for PTSD and depression in more depth. Second, some potential confounding factors were not measured or adjusted for in the analysis, such as coping style, other life events, etc. Third, our sampling was not completely random. The inclusion of persons for whom participation was convenient raises the possibility of self-selection bias. Finally, the IES-R is a screening tool, rather than a clinical diagnostic method; thus, the prevalences of PTSD and depression were probably somewhat overestimated in our study. Future research should, if possible, emphasize the role of clinical diagnostic measurements when exploring similar topics, so as to increase the credibility of the findings among clinicians.
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Anxiety Disord. 28, 75–82. Hong, C., Efferth, T., 2015. Systematic review on. Trauma Violence Abus.. Hou, S.K., Lv, Q., Ding, H., Zhang, Y.Z., Yu, B.G., Liu, Z.Q., Su, B., Liu, J.Y., Yu, M.Y., Sun, Z.G., 2016. Disaster medicine in China: present and future. Disaster Med. Public Health Prep. 1, 1–9. Jin, J., 2014. Seismic mortality estimation in China: a comparison of three empirical models. Adv. Mater. Res. 1073–1076, 1557–1561. Jovanovic, T., Norrholm, S.D., Blanding, N.Q., Davis, M., Duncan, E., Bradley, B., Ressler, K.J., 2010. Impaired fear inhibition is a biomarker of PTSD but not depression. Depression Anxiety 27, 244–251. Kaltman, S., Green, B.L., Mete, M., Shara, N., Miranda, J., 2010. Trauma, depression, and comorbid PTSD/depression in a community sample of Latina immigrants. Psychol. Trauma: Theory Res. Pract. Policy 2, 31–39. Kun, P., Chen, X., Han, S., Gong, X., Chen, M., Zhang, W., Yao, L., 2009. Prevalence of post-traumatic stress disorder in Sichuan Province, China after the 2008 Wenchuan earthquake. Public Health 123, 703–707. Lonergan, M., 2014. Cognitive behavioral therapy for PTSD: the role of complex PTSD on treatment outcome. J. Aggress. Maltreatment Trauma 23, 494–512. O'Donnell, M.L., Creamer, M., Pattison, P., 2004. Posttraumatic stress disorder and depression following trauma: understanding comorbidity. Am. J. Psychiatry 161, 1390–1396. Olff, M., Langeland, W., Draijer, N., Gersons, B.P., 2007. Gender differences in posttraumatic stress disorder. Psychol. Bull. 133, 183–204. Qu, Z., Tian, D., Zhang, Q., Wang, X., He, H., Zhang, X., Huang, L., Xu, F., 2012a. The impact of the catastrophic earthquake in China's Sichuan province on the mental health of pregnant women. J. Affect. Disord. 136, 117–123. Qu, Z., Wang, X., Tian, D., Zhao, Y., Zhang, Q., He, H., Zhang, X., Xu, F., Guo, S., 2012b. Posttraumatic stress disorder and depression among new mothers at 8 months later of the 2008 Sichuan earthquake in China. Arch. Women's Ment. Health 15, 49–55. State Council Information Office of China (SCIOC), 2008. Report of the progress of postdisaster relief after the Wenchuan earthquake. Tang, B., Liu, X., Liu, Y., Chen, X., Zhang, L., 2014. A meta-analysis of risk factors for depression in adults and children after natural disasters. BMC Public Health 14, (623–623). Wang, X., 1999. Psychological assessment scale manual. Chin. Ment. Health J., 200–202. Wang, L., Zhang, Y., Wang, W., Shi, Z., Shen, J., Li, M., Xin, Y., 2009. Symptoms of posttraumatic stress disorder among adult survivors three months after the Sichuan earthquake in China. J. Trauma. Stress 22, 444–450. Wang, B., Ni, C., Chen, J., Liu, X., Wang, A., Shao, Z., Xiao, D., Cheng, H., Jiang, J., Yan, Y., 2011. Posttraumatic stress disorder 1 month after 2008 earthquake in China: wenchuan earthquake survey. 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6. Conclusions The results of this study indicate that PTSD and depression are long-term mental health sequelae of the Wenchuan earthquake among its survivors, even after eight years. Different sets of risk factors are associated with symptomalogical PTSD and depression among adult earthquake survivors. Objective exposure is associated with chronic comorbid symptomalogical PTSD and depression, while subjective exposure is associated with long-term depression. These findings may have implications for future post-earthquake mental health programs. Disclosure statement No competing financial interests exist. Contributors JG drafted the manuscript. ZQ, XW, and CL were involved in the design of this study, research instrument development, and data collection. HH was involved the data analysis and revised the manuscript. All authors were involved in writing the manuscript and approve of its final version. Funding This study was supported by National Natural Science Foundation of China (31500912). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Acknowledgments The authors wish to thank Ms. Cordelia Fuller for her careful edit of the paper, and thank all those who helped to collect the data and those who kindly volunteered to participate in the study. The authors further wish to express their deepest condolences to all of the families and individuals who lost family members or relatives in the 2008 Sichuan earthquake disaster. References Bromet, E.J., Atwoli, L., Kawakami, N., Navarro-Mateu, F., Piotrowski, P., King, A.J.,
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after the 512 Wenchuan earthquake in China. PLoS One 6, e22371. Zhang, Z., Shi, Z., Wang, L., Liu, M., 2011. One year later: mental health problems among survivors in hard-hit areas of the Wenchuan earthquake. Public Health 125, 293–300. Zhang, J., Wu, Z., Fang, G., Li, J., Han, B.X., 2010. Development of the Chinese age norms of CES-D in urban area. Chin. Ment. Health J. 24, 139–143. Zimering, R., Gulliver, S.B., Knight, J., Munroe, J., Keane, T.M., 2006. Posttraumatic stress disorder in disaster relief workers following direct and indirect trauma exposure to Ground Zero*. J. Trauma. Stress 19, 553–557. Zoellner, L.A., Pruitt, L.D., Farach, F.J., Janie, J.J.M.S., 2014. Understanding heterogenelity in PTSD: fear, dysphoria, and distress. Depression Anxiety 31, 97–106.
Keane, T.M. (Eds.), Assessing Psychological Trauma and PTSD: A Practitioner's Handbook. Guilford Press, N Y. Wohlfarth, T.D., van den Brink, W., Winkel, F.W., ter Smitten, M., 2003. Screening for posttraumatic stress disorder: an evaluation of two self-report scales among crime victims. Psychol. Assess. 15, 101–109. Wu, K.K., Chan, K.S., 2003. The development of the Chinese version of impact of event scale–revised (CIES-R). Soc. Psychiatry Psychiatr. Epidemiol. 38, 94–98. Wu, Z., Xu, J., He, L., 2013. Psychological consequences and associated risk factors among adult survivors of the 2008 Wenchuan earthquake. BMC Psychiatry 14, 158–159. Xiao, Z.L., Wen, J., Zhao, H., Tan, Q.W., LV, X., Yan, Fb, 2011. A bibliometric analysis on post-earthquake health issue related literature. Chin. J. Evid. Based Med. 11. Zhang, Y., Ho, S., 2011. Risk factors of posttraumatic stress disorder among survivors
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Contents lists available at ScienceDirect
Journal of Affective Disorders journal homepage: www.elsevier.com/locate/jad
Research paper
Post-traumatic stress disorder and depression among adult survivors 8 years after the 2008 Wenchuan earthquake in China
MARK
⁎
Jing Guoa, , Huan Heb, Zhiyong Quc, Xiaohua Wangc, Chengbin Liua a b c
School of Sociology, Huazhong University of Science and Technology, Wuhan 430074, PR China Department of Public Administration, Southwestern University of Finance and Economics, Chengdou 610074, PR China School of Social Development and Public Policy, China Institute of Health, Beijing Normal University, Beijing 100875, PR China
A R T I C L E I N F O
A BS T RAC T
Keywords: PTSD Depression Earthquake
Background: The Wenchuan earthquake was China's worst natural disaster of the past three decades. Although the psychological sequelae of disasters can last for many years, the long-term sequelae and their risk factors tend to receive little research attention. Objectives: The objectives of the present study were to estimate the prevalences of symptomalogical PTSD and depression among survivors 8 years after the Wenchuan earthquake, and to identify the shared and unshared risk factors associated with PTSD and depression, using data from a cross-sectional survey. Methods: 1369 participants were recruited from two different sites in the areas that were severely affected by the earthquake. Symptomalogical PTSD was assessed by the Impact of Event Scale-Revised (IES-R). The Chinese edition of the Center for Epidemiologic Studies Depression Scale (CES-D) was used to assess depression. Traumatic exposure to the Wenchuan earthquake was assessed using an exposure checklist designed by this study. Results: Eight years after the Wenchuan earthquake, 11.8% of the respondents had symptomalogical PTSD, and 24.8% of respondents had probable depression. The results also indicated that female gender, low education, poor perceived health, and traumatic experiences after the earthquake were associated with higher odds of both PTSD and depression among survivors. Direct exposure to the earthquake was associated with comorbid symptomalogical PTSD and depression (OR=1.86; 95% CI=1.42, 2.44). Those having only depression were more likely to be unmarried/divorced/widowed, and to have experienced fear at the time of the earthquake (OR=1.34; 95% CI=1.04, 1.72), while those with only symptomalogical PTSD were likely to be from the township of Yongan as opposed to Guangji (OR=1.86; 95% CI=1.06, 3.31). Limitations: This is a cross-sectional study, and thus is insufficient for determining causal relationships with regard to chronic PTSD or depression. Conclusions: The results of this study indicate that symptomalogical PTSD and depression persist among many survivors of the Wenchuan earthquake, 8 eight years later. Objective earthquake exposure is associated with symptomalogical PTSD, while subjective exposure is associated with long-term depression.
1. Introduction Globally, people in less developed countries and regions are more likely to be affected by natural disasters, and a huge number of people die from all kinds of disasters in these countries (Wang et al., 2000). However, due to limited financial support and public attention, little post-disaster research is conducted in developing countries. China is an earthquake-prone country, and since 1950, half of the deaths that were caused by natural disasters in China were caused by earthquakes, which also caused great economic damage (Hou et al., 2016; Jin,
⁎
2014). PTSD and depression are the most common mental disorders following earthquakes. PTSD prevalence estimates vary widely, with most being in the 20–40% range, in disaster-focused studies (Bromet et al., 2016). Recent reviews have suggested that nearly 1 in 4 earthquake survivors develop PTSD (Dai et al., 2016). Considering these facts, there is a need for more research on the mental health consequences of severe earthquakes in China. The Wenchuan earthquake was China's worst natural disaster of the past three decades. On May 12, 2008, a magnitude 8.0 earthquake struck the area around Wenchuan County, in the northwestern part of
Corresponding author. E-mail address: [email protected] (J. Guo).
http://dx.doi.org/10.1016/j.jad.2016.12.009 Received 17 August 2016; Received in revised form 22 October 2016; Accepted 12 December 2016 Available online 16 December 2016 0165-0327/ © 2016 Elsevier B.V. All rights reserved.
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conducted among survivors of the 2008 Wenchuan earthquake in February 2016, eight years later. Participants were recruited from two different sites in the area that was severely affected by the earthquake. The first survey site was the township of Yongan (115.7 km from the epicenter) in Beichuan County, which is located in a mountainous area. Over 90% of the buildings in Yongan were damaged in the earthquake. The earthquake killed 15,645 people and left 26,916 people injured, and 1023 missing in Beichuan County. The second site was the township of Guangji (58.3 km from the epicenter) in Mianzhu County, which is located on a plain. Over 96% of the buildings in Guangji were damaged in the earthquake. It has been confirmed that 11,098 people were killed, 36,468 people were injured, and 298 people missing in Mianzhu County. These two townships were selected because both are close to the epicenter but at somewhat different distances, both suffered severe destruction in the earthquake, and both had similar socioeconomic and demographic characteristics before the earthquake. This cross-sectional study used a combined multistage systematic sampling and convenience sampling design to select participants. In the first stage, 12 of the total 29 villages were randomly selected from the two survey townships. In the second stage, households, rather than individuals, were systematically selected, using village registration information, as the basic unit for the entire survey. But in a small number of villages, many former residents were no longer residing in their homes, making such systematic sampling unfeasible; in these villages, non-random sampling methods were therefore also used. Adults over age 16 in each household were selected for participation. The actual samples achieved amounted to a total of 1369 adults. A higher than 90% response rate was achieved. These samples were representative of two townships that were severely affected by the Wenchuan earthquake. Face-to-face interviews were conducted, in Mandarin Chinese and in the local dialects and languages, by 22 college students from Mainyang Normal University. All of the interviewers were thoroughly trained before the survey. The training involved the following five sessions: introduction, sampling design and procedures, review of the questionnaire, methods and techniques of interviewing, and potential difficulties in conducting the survey. The interviewers were required to show their identification and explain the aims of the study prior to requesting permission to enter the participants' houses. They read each question out to the respondents, and then wrote down their answers on the questionnaire. The average interview time was 1 h. The study protocol was approved by the Institutional Review Board of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China. All participants gave consent after being informed about the aim of the survey and their right to refuse to participate.
Sichuan province. It left 69,227 people dead, 374,643 injured, 17,923 missing, and millions homeless (SCIOC, 2008). Large studies showed that PTSD was the most prevalent mental disorder among survivors of the Wenchuan earthquake (Hong and Efferth, 2015). Kun et al. (2009) reported that the prevalence of probable Post-traumatic Stress Disorder (PTSD) was 45.5% in the heavily damaged Beichuan County two and half months after the earthquake. Studies of the impact of the Wenchuan earthquake on the mental health of its survivors found that female gender, older age, lower household income, ethnic minority status, low educational level, living in a shelter or temporary house, death or a bodily injury in one's family, and household damage, were important risk factors associated with PTSD among adults (Kun et al., 2009; Wang et al., 2009; Zhang and Ho, 2011; Zhang et al., 2011). Disaster-related psychological sequelae can last for many years, but the long term sequelae and their risk factors tend to receive little research attention. A recent systematic review found that the number of journal articles published on the health consequences of an earthquake tend to drop dramatically 2 years after its occurrence (Xiao et al., 2011). To the best of our knowledge, very few studies to date have focused on the long term mental health effects of this disaster. Eight years have passed, and no existing study has examined the long term prevalences of mental disorders and related predictors among Chinese adult earthquake survivors. More research on the long-term psychiatric outcomes of the Wenchuan earthquake is needed. The following three factors are potential predictors of symptomalogical PTSD following an earthquake: traumatic experience(s) before the earthquake, traumatic exposure to the earthquake, and traumatic experience(s) after the earthquake (Cénat and Derivois, 2015). In previous studies, the term “direct exposure” referred to experiencing or witnessing the traumatic stressor, and “indirect exposure” was defined as learning about “death, serious harm, or threat of death or injury experienced by a family member or other close associate” (Zimering et al., 2006). Other studies have indicated that traumatic stress scores are associated with high subjective fear during exposure (Lonergan, 2014). In this study, we defined subjective exposure as fear at the time of the earthquake. Although many studies have found that direct and indirect exposure are highly associated with both depressive and Symptomalogical PTSD (Zimering et al., 2006), findings about the relationship of PTSD and depression to subjective exposure have been inconsistent. For example, one study suggested that impaired fear inhibition may be a specific biomarker of Symptomalogical PTSD (Jovanovic et al., 2010). Another study found during-disaster fear to be highly correlated with depression (Tang et al., 2014). The difference in findings may be due to differences in cultural context, study design, and/or sampling methods. In addition, some studies have compared the shared and unshared predictors of depressive and symptomalogical PTSD among adult earthquake survivors. One study found that being female, having a low income level and having a low perceived level of social support were all associated with both depression and PTSD (Wu et al., 2013). Another study found traumas such as loss of both parents and, to a lesser degree, loss of a father to be significant risk factors for depression, but not for PTSD, among adolescents (Goenjian et al., 2009). To what extent do these findings apply to survivors of the 2008 earthquake in China? The objectives of the present study were to estimate the prevalences of symptomalogical PTSD and depression among survivors 8 years after the Wenchuan earthquake, and to identify the shared and unshared risk factors associated with PTSD and depression, using data from a cross-sectional survey.
3. Measurement 3.1. Main outcome measures Probable Symptomalogical PTSD: symptomalogical PTSD was assessed by the Impact of Event Scale-Revised (IES-R) (Weiss and Marmar, 1997), a self-report instrument widely used in the field of traumatic stress. It includes 22 items used to measure the three major symptom clusters of PTSD: Intrusion, avoidance, and hyper-arousal. The IES-R's measures have been found to have good and stable psychometric properties (Creamer et al., 2003). The Chinese version of the IES-R has been found to have satisfactory psychometric properties, comparable to those of the original English version (Chen et al., 2007; Wu and Chan, 2003). In this study, the IES scale was used to investigate only posttraumatic symptoms related to the Wenchuan earthquake. The participants were asked to indicate the frequency of their distress using 4 response options (0=not at all, 1=seldom, 3=sometimes, 5=often) (Chan et al., 2012; Chan et al., 2011, 2012;
2. Methods 2.1. Study design and participants This study is based on a community-based, cross-sectional survey 28
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earthquake. Traumatic experience before the earthquake (Pre-quake trauma) was assessed using the yes/no question: “Did you experience any traumatic event before the earthquake? ” Traumatic experience after the earthquake (Post-quake trauma) was assessed using: “Did you experience any traumatic event after the Wenchuan earthquake? ” Demographic and socioeconomic variables: The following demographic and socioeconomic information was also collected in the survey: Township of residence (Yongan/Guangji); gender (female/ male); ethnicity (Han vs. Minority, with the latter including Qiang, Tibetan, Hui, Mongol and other minority groups); age (16–35 years/ 35–55 years/ > 55 years); marital status (married/unmarried/other status); educational level (primary school or below /middle school or above); self-reported household income (low/middle/high); self-reported perceived health (good/poor). These variables were included in the analyses because they have been examined in prior related studies (Kun et al., 2009; Wang et al., 2009; Zhang and Ho, 2011; Zhang et al., 2011).
Qu et al., 2012a; Qu et al., 2012a, 2012b). Subscale scores were calculated as the means of the responses to all of the items in the specific subscale, and the total score was calculated as the mean response across all items. Since there is no recommended cutoff point for the IES-R (Christianson and Marren, 2012), this study adopted a mean score of 2.0 across all items of the IES-R as the cutoff point, as was done in earlier studies (Chan et al., 2011; Guo et al., 2015; Qu et al., 2012a; Qu et al., 2012a, 2012b). One earlier study using this cutoff point reported a sensitivity of 0.89 and a specificity of 0.90 (Wohlfarth et al., 2003). The internal consistency coefficient (Cronbach's alpha) of the whole scale in the present study was 0.93. Depression: The Chinese edition of the Center for Epidemiologic Studies Depression Scale (CES-D) (Wang, 1999) was used to assess probable depression. This scale is the most widely used depressionscreening scale and has been used in many community-based studies. The Chinese version of the CES-D scale has shown good reliability and validity across all age groups in urban populations (Zhang et al., 2010). In our study, we used 21 as the cutoff point, as this has been shown to be a good predictor of depression in Chinese populations (Cheng and Chan, 2005). The internal consistency coefficient (Cronbach's alpha) of the whole scale in the present study was 0.88.
3.4. Statistical analysis SPSS 22.0 (SPSS Inc, Chicago, IL) was used for statistical analysis. Descriptive statistics were calculated for all of the socio-demographic and confounding variables. Univariate regression analysis was conducted to determine whether symptomalogical PTSD and depression were significantly associated with any of the socio-demographic variables and numbers of exposures. Binary logistic regression analysis was used to examine the effects of the risk factors on symptomalogical PTSD and depression. Then, the whole sample was divided into four groups: PTSD only, depression only, PTSD and depression, and No diagnosis. Multinomial logistic regression analysis was used to identify whether particular mental health status categories were associated with different groups of predictors. All p values were derived from adjusted Wald F tests based on these regression models. These analyses allowed us to meet the objectives outlined in the introduction to this paper.
3.2. Main measures of independent variables Traumatic exposure to the Wenchuan earthquake was assessed using an exposure checklist. We developed this measure, with the help of suggestions from five experts in the field, and some Wenchuan earthquake survivors. It has 12 items, covering three dimensions: direct exposure, indirect exposure, and subjective exposure. Direct exposure refers to respondents’ having been trapped or injured, or seen others thus exposed, during the earthquake. Indirect exposure refers to their family members, friends or being directly exposed to the earthquake. Subjective exposure refers to the participants’ having been afraid, during the earthquake, of being trapped, injured, or killed. The participants were asked to answer “yes” or “no” regarding each kind of exposure (See Table 1).
4. Results 4.1. Descriptive analysis
3.3. Potential confounders The respondents to the survey were mainly female, married, and members of the Han ethnic group, which makes up most of the population of China. Also, because the surveyed townships were both located in a rural area, most of the participants were farm workers with relatively low levels of education. The median age of the participants was 56 years and their mean age was 54.34 years (SD=15.9).13.1% of the participants were religious, most of them being Buddhists. 28.1% of the participants considered their family incomes to be low. The overall prevalences of symptomalogical PTSD and depression were 11.8% and 24.8%, respectively. Rates of symptomalogical PTSD were significantly higher among those from Yongan, and among female, middle aged, married, less educated, and low income participants. In addition, rates of depression were significantly higher among religious, older, divorced/widowed, and less educated participants. Respondents who had experienced traumatic events before the quake were more than 1.59 times as likely to exhibit symptomalogical PTSD compared to those with no pre-quake traumatic experiences (95% CI=1.14, 2.21). Those who had experienced traumatic events after the earthquake (OR=1.93; 95% CI=1.32, 2.84) were more likely to exhibit symptomalogical PTSD than other respondents. In addition, those who had experienced traumatic events after the earthquake were 2.35 times more likely to have depression than those who had not. (95% CI=1.74, 3.16) (Table 2). As illustrated in Fig. 1, the prevalence of symptomalogical PTSD only was 5.3% at 8 years after the earthquake, while the prevalences of depression only, and of symptomalogical PTSD with depression, were 18.4% and 6.4% respectively. Females were more likely to have
Three factors that can affect the mental health of earthquake survivors include: traumatic experiences before the earthquake, traumatic exposure to the earthquake, and traumatic experiences after the Table 1 Exposures to the Wenchuan earthquake among adult survivors. Dimensions
Direct exposure
Indirect exposure
Subjective exposure
Items
1. Were you trapped? 2. Were you injured? 3. Did you see someone trapped? 4. Did you see someone die or be injured? 5. Did you have family members who were trapped? 6. Did you have family members who were injured? 7. Did you have family members who died? 8. Did you have relatives or friends who were trapped? 9. Did you have relatives or friends who were injured? 10. Did you have relatives or friends who died? 11. Did you fear being trapped, injured, or killed? 12. Did you fear that someone else would be trapped, injured, or killed?
Score 0
1
No No No No No
Yes Yes Yes Yes Yes
No
Yes
No No
Yes Yes
No
Yes
No
Yes
No
Yes
No
Yes
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Table 2 Sample characteristics and odds of PTSD and depression eight years after the Wenchuan earthquake in China. Total N (%)
PTSD N (%)
OR (95% CI)
Depression N (%)
OR (95% CI)
Total Location Guangji Yongan
1369 (100) 677 (49.5) 692 (50.5)
161 (11.8) 57 (8.4) 104 (15.0)
1 1.92 (1.37, 2.71)***
340 (24.8) 162 (23.9) 178 (25.7)
1 1.01 (0.86, 1.41)
Gender Male Female
632 (46.6) 725 (53.4)
49 (7.8) 107 (14.8)
1 2.06 (1.44, 2.94)***
123 (19.5) 212 (29.2)
1 1.71 (1.33, 2.20)**
Ethnicity Han Minority
1283 (94.6) 73 (5.4)
146 (11.4) 12 (16.4)
1 1.53 (0.81, 2.91)
317 (24.7) 18 (24.7)
1 0.99 (0.58, 1.72)
Religion No Yes
1181 (86.9) 178 (13.1)
137 (11.6) 23 (12.9)
1 1.13 (0.71, 1.81)
279 (23.6) 57 (32.0)
1 1.52 (1.08, 2.15)*
Age 16–35 35–55 > 55
151 (11.8) 484 (35.8) 644 (50.4)
9 (6.0) 64 (13.2) 70 (10.9)
1 2.40 (1.17,4.96)* 1.93 (0.94,3.05)
21 (13.9) 115 (23.8) 174 (27.0)
1 1.93 (1.16, 3.20)* 2.29 (1.40, 3.75)***
Marital status Unmarried/others Married
234 (17.4) 1109 (82.6)
16 (6.8) 142 (12.8)
1 2.00 (1.17,3.42)*
74 (31.6) 256 (23.1)
1 0.65 (0.48, 0.88)**
Education Middle/above Primary/below
414 (30.5) 942 (69.5)
26 (6.3) 133 (14.1)
1 2.45 (1.58, 3.80)***
57 (13.8) 276 (29.3)
1 2.60 (1.90, 3.55)***
Income Rich Middle Poor
115 (8.5) 861 (63.4) 381 (28.1)
7 (6.1) 87 (10.1) 64 (16.8)
1 1.73 (0.78, 3.84) 3.11 (1.39, 7.00)
26 (22.6) 163 (18.9) 150 (39.4)
1 0.80 (0.50, 1.28) 2.22 (1.37, 3.60)
Perceived health Good Poor
950 (69.6) 415 (30.4)
84 (8.8) 77 (18.6)
1 2.35 (1.68, 3.28)
186 (19.6) 153 (36.9)
1 2.40 (1.86, 3.10)
Pre-quake trauma No Yes
842 (61.5) 527 (38.5)
83 (9.9) 78 (14.8)
1 1.59 (1.14, 2.21)**
199 (23.6) 141 (26.8)
1 1.18 (0.92, 1.52)
Post-quake trauma No Yes
1117 (82.7) 233 (17.3)
117 (10.5) 43 (18.5)
1 1.93 (1.32, 2.84)***
243 (21.8) 92 (39.5)
1 2.35 (1.74, 3.16)***
Note: N, number; OR, odds ratio; 95% CI, confidence interval. *** P < 0.001. ** P < 0.01. * P < 0.05.
symptomalogical PTSD than males.
4.2. Regression analysis Table 3 presents the results of the multivariate logistic analysis assessing the risk factors for symptomalogical PTSD and depression. The independent variables included numbers of direct exposure, indirect exposure, and subjective exposure. Potentially confounding variables included in the model were socio-economic variables, perceived health, and traumatic experience before/after the earthquake. With these variables controlled for, post-quake traumatic experience was significantly associated with both depression and PTSD. However, direct exposure (OR=1.59; 95% CI=1.30, 1.96) was only significantly associated with probable PTSD. Having experienced high fear at the time of the earthquake was a significant risk factor for depression (OR=1.32; 95% CI=1.05, 1.66), but not for PTSD. Table 4 displays the results of the multi-nominal logistic regression analysis. As compared with participants with no diagnosis, those with
Fig. 1. Prevalence of PTSD and depression among adult survivors eight years after the Wenchuan earthquake (%).
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5. Discussion
Table 3 Logistic Regression results for risk factors of PTSD and depression among adult survivors eight years after the Wenchuan earthquake in China. PTSD
Direct exposure
a
b
Indirect exposure
Subjective exposurec
Town (Ref: Guangji) Yongan
OR (95% CI)
P-value
OR (95% CI)
P-value
1.59 (1.30, 1.96) 1.12 (0.98, 1.28) 1.08 (0.80, 1.46)
< 0.001
1.13 (0.95, 1.35) 1.02 (0.92, 1.14) 1.32 (1.05, 1.66)
0.173
0.110 0.615
0.685 0.016
1.57 (1.04, 2.35)
0.031
1.01 (0.75, 1.37)
0.933
1.80 (1.19, 2.73)
0.006
1.55 (1.15, 2.10)
0.004
1.10 (0.46, 2.64) 0.93 (0.37, 2.30)
0.832
1.38 (0.71, 2.69) 1.28 (0.66, 2.50)
0.336
0.91 (0.41, 2.01)
0.812
0.90 (0.46, 1.77)
0.758
0.62 (0.34, 1.15)
0.128
0.83 (0.54, 1.27)
0.382
Marital status (Ref: Unmarried/others) Married 2.26 (1.15, 4.46)
0.018
0.50 (0.34, 0.74)
0.001
Education (Ref: Middle school or above) Prim-school/below 2.15 (1.22, 3.80)
0.008
2.37 (1.56, 3.60)
< 0.001
2.28 (0.92, 5.69) 1.35 (0.56, 3.30)
0.077
1.57 (0.90, 2.76) 0.70 (0.41, 1.21)
0.114
1.82 (1.22, 2.74)
0.004
2.00 (1.48, 2.71)
< 0.001
1.10 (0.73, 1.64)
0.653
0.96 (0.71, 1.30)
0.781
1.81 (1.15, 2.86)
0.010
2.05 (1.44, 2.92)
< 0.001
Gender (Ref: Male) Female
Age (Ref: 16–35) 35–55 > 55
Ethnicity (Ref: Han) Minority
Religion (Ref: No) Yes
Income (Ref: High) Low Middle
Perceived health (Ref: Good) Poor
Pre-quake trauma (Ref: No) Yes
Post-quake trauma (Ref: No) Yes
Our study, conducted eight years after the Wenchuan earthquake, allowed us to learn more about the psychological sequelae associated with a large-scale disaster in a developing country. In this study, symptomalogical PTSD and depression were evaluated by valid measurement tools. Various levels of earthquake exposure were also assessed. Our results show that the prevalences of symptomalogical PTSD and depression remained high 8 years after the earthquake among the adult survivors. The findings reported here also suggest that direct and other types of earthquake exposure variables affected chronic symptomalogical PTSD and comorbid symptomalogical PTSD and depression, while high fear at the time of the earthquake only had a long-term effect on depression. These findings illustrate the importance of studying the prevalences and risk factors for PTSD and depression among earthquake survivors in developing countries. Firstly, the study found that the survivors had long-term psychiatric morbidity, even 8 years after the earthquake. Examination of the longterm prevalence of PTSD was lacking in prior studies. One study conducted among adult survivors 10–11 years after the 9/11 attacks found that 15.2% of respondents reported symptoms indicative of PTSD and 14.9% met criteria for depression; 10.1% experienced both (Caramanica et al., 2014). Our own prior study showed that 8.0% of earthquake survivors had PTSD symptoms 44 months after the Wenchuan earthquake (Guo et al., 2013). The present study found that the prevalence of symptomalogical PTSD was 11.8% eight years after the earthquake, while the prevalences of depression and comorbid PTSD and depression were 24.8% and 6.4% respectively. The PTSD prevalence found in this study is a little higher than our prior study. Such variability is maybe partially explained by changes in the nature of the sample. Because some young subjects migrated out of the area, looking for work, after the earthquake, the mean age of the current study's participants is older than in the previous study. But these results certainly show that PTSD rates did not decline in the area in the years after the first study was conducted, and depression was more common than PTSD among adult survivors 8 years after the Wenchuan earthquake. Researchers, health care professionals, and the public should be aware that affected individuals may continue to present earthquake-related trauma symptoms long after the event; ongoing surveillance and services are needed. Secondly, the findings indicate that female gender, low education, poor perceived health, and traumatic experience after the earthquake are associated with both PTSD and depression among survivors. This is consistent with prior studies. Research findings on the role of gender in the prediction of PTSD symptoms following earthquakes in adult populations have shown higher vulnerability in women (Dell'Osso et al., 2011). Explanations offered in prior studies suggest that women's higher risk of PTSD & depression may be due to their stronger perceptions of threat and loss of control, higher levels of peri traumatic dissociation, and gender-specific acute psychobiological reactions to trauma (Gavranidou and Rosner, 2003; Olff et al., 2007). Groups with low education and poor perceived health tend to have longer-lasting mental health problems. The reason maybe that these vulnerable groups lack the ability to recover from the disaster. Misfortunes never come singly. Survivors who experience another traumatic event again after an earthquake are more sensitive to the experience. This is why they are more likely to have persistent depressive and PTSD symptoms. The Wenchuan earthquake was the second most destructive earthquake to hit China to date, and the results of this study have implications for policy and planning. Health care providers, researchers, and government officials need to continue to address the mental health needs of vulnerable subgroups of those affected, such as female survivors and survivors with more types of disaster exposures. Thirdly, this study reveals there are differential constructs for PTSD and depression among adult survivors following the Wenchuan earthquake. The findings of studies on the risk factors for PTSD and
Depression
0.872
0.503
0.467
0.203
Note: a, b, c: Reference: numbers of exposure.
depression only were likely to be unmarried/divorced/widowed, and to have experienced high fear at the time of the earthquake (OR=1.34; 95% CI=1.04, 1.72), while those with symptomalogical PTSD only were likely to be from Yongan (OR=1.86; 95% CI=1.06, 3.31). Moreover, those with direct exposures to the earthquake (OR=1.86; 95% CI=1.42, 2.44) were more likely to have comorbid depression and PTSD. In addition, female gender and post-quake traumatic event were positively associated with each of the probable diagnoses of PTSD only, depression only, and PTSD with depression.
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Table 4 Results of multi-nominal logistic regression of risk factors for PTSD only, depression only, and PTSD with depression among adults eight years after the Wenchuan earthquake in China. Only Depression (N=252)
Only PTSD (N=73)
PTSD & Depression (N=88)
ORa (95% CI)
P-value
ORa (95% CI)
P-value
ORa (95% CI)
P-value
Direct exposure Indirect exposure Subjective exposure
0.93(0.74, 1.16) 1.02(0.90, 1.16) 1.34(1.04, 1.72)
0.500 0.755 0.022
1.28(0.95, 1.72) 1.17(0.98, 1.41) 1.05(0.71, 1.55)
0.104 0.088 0.809
1.86(1.42, 2.44) 1.09(0.90, 1.31) 1.30(0.83, 2.04)
< 0.001 0.384 0.258
Town (Ref: Guangji) Yongan
1.00(0.72, 1.39)
0.988
1.86(1.06, 3.28)
0.031
1.31(0.75, 2.30)
0.349
Gender (Ref: Male) Female
1.52 (1.09, 2.11)
0.013
1.87 (1.06, 3.31)
0.032
2.08 (1.16, 3.71)
0.014
Age (Ref: 16–35) 35–55 > 55
0.70 (0.34, 1.45) 1.11 (0.77, 1.59)
0.334 0.589
0.90 (0.28, 2.83) 1.32 (0.73, 2.39)
0.851 0.355
1.40 (0.34, 5.76) 1.16 (0.64, 2.09)
0.638 0.628
Ethnicity (Ref: Han) Minority
0.87 (0.39, 1.92)
0.731
0.87 (0.31, 2.46)
0.790
0.86 (0.28, 2.70)
0.800
Religion (Ref: No) Yes
0.85 (0.53, 1.37)
0.511
0.55 (0.21, 1.47)
0.234
0.58 (0.26, 1.26)
0.166
Marital status (Ref: Unmarried/others) Married 0.43 (0.29, 0.65)
< 0.001
2.30 (0.78, 6.80)
0.132
1.35 (0.57, 3.21)
0.492
Education (Ref: Middle school or above) Primary school/ below 2.01 (1.28, 3.14)
0.002
1.48 (0.75, 2.93)
0.258
5.83 (2.16, 15.74)
< 0.001
Income (Ref: Rich) Poor Middle
1.59 (0.85, 2.98) 0.84 (0.46, 1.52)
0.147 0.560
5.20 (0.66, 40.72) 5.34 (0.72, 39.78)
0.117 0.102
1.82 (0.65, 5.11) 0.49 (0.17, 1.38)
0.253 0.175
Perceived health (Ref: Good) Poor
1.84 (1.31, 2.58)
< 0.001
1.47 (0.82, 2.62)
0.196
3.03 (1.73, 5.31)
< 0.001
Pre-quake trauma (Ref: No) Yes
0.87 (0.62, 1.21)
0.405
0.88 (0.50, 1.55)
0.655
1.26 (0.72, 2.18)
0.422
Post-quake trauma (Ref: No) Yes
2.35 (1.59, 3.47)
< 0.001
2.69 (1.46, 4.94)
0.001
2.00 (1.06, 3.81)
0.034
Note: a Compared to “neither PTSD nor depression” cases (N=956).
require further study. Better understanding the similarities and differences between the risk factors for PTSD and depression will help in developing more targeted, specific interventions after the disasters. Finally, we developed an exposure checklist in this study. Many studies have used the concepts of direct and indirect exposure in assessing levels of exposure to disasters (Zoellner et al., 2014). We decided to use subjective perceived exposure as an exposure measure. In this study, we found that objective exposure is associated with chronic symptomalogical PTSD and its comorbidity with depression, while subjective perceived exposure is associated with long-term depression. This shows that objective and subjective exposure may have different effects on the psychological sequelae of disasters. Our checklist has twelve simple items. It can be used by social workers and public health workers to conduct rapid evaluation of individuals’ exposures to an earthquake. It should be noted that this tool needs further development and should be examined in further studies. The findings of this study contribute to extant knowledge on the long-term mental health consequences of natural disasters. The observed high prevalences of PTSD, depression, and comorbid PTSD and depression among these earthquake survivors demonstrate the need for continued mental health research, screening and treatment, especially among vulnerable groups in disaster-prone areas. Additionally, our findings indicate that PTSD and depression together constitute a general psychiatric response to trauma, and that the factors that predict PTSD are different from those that predict
depression have been inconsistent. O'Donnell et al. (2004) examined the factors predicting PTSD and depression among traumatic injury survivors, and found that similar sets of factors were predictive of each of these two conditions. However, Kaltman et al. (2010) conducted a study among Latina immigrants to the United States, and found that quite different sets of factors correlated with each of these two conditions. Our results are consistent with Kaltman's. We found that long-term depression was associated with high fear at the time of the earthquake, while chronic symptomalogical PTSD was associated with being from Yongan. Moreover, those with direct exposures to the earthquake were more likely to have comorbid depression and PTSD. This may be explained by a strong association between depression and subjective memories of fear, with PTSD being more associated with objective exposure. Compared to Guangji residents, Yongan residents were more likely to have chronic symptomalogical PTSD. Perhaps this has to do with Yongan's being located in a mountainous area, while Guangji residents live on flatter ground. Moreover, the results of the binary regression analysis indicated that unmarried/divorced/widowed people were more likely to have depression, while married people were more likely to have PTSD. A possible reason may be that marriage is a double-edged sword. Unmarried/divorced/widowed people lack support against negative emotions or depressive symptoms, but married people tend to be extremely worried about harm to their family members and possessions in a disaster (Wang et al., 2011). The specifics of the longitudinal relationship between PTSD and depression 32
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depression. This finding has potential clinical implications for improved treatment of these conditions, as comorbidity of PTSD and depression has been shown to have implications in terms of treatment efficacy and biological profile. To the authors' knowledge, this study is among the first investigations of the long-term mental health effects of an earthquake among survivors; it is also one of a handful of studies of the psychological sequelae of catastrophic natural disasters among populations not from Western countries. Besides these strengths, the present study has several limitations that should be mentioned. First, it is a cross-sectional study, and is thus insufficient for determining causal relationships with regard to chronic PTSD. Future studies, using longitudinal data, are needed to explore the risk factors for PTSD and depression in more depth. Second, some potential confounding factors were not measured or adjusted for in the analysis, such as coping style, other life events, etc. Third, our sampling was not completely random. The inclusion of persons for whom participation was convenient raises the possibility of self-selection bias. Finally, the IES-R is a screening tool, rather than a clinical diagnostic method; thus, the prevalences of PTSD and depression were probably somewhat overestimated in our study. Future research should, if possible, emphasize the role of clinical diagnostic measurements when exploring similar topics, so as to increase the credibility of the findings among clinicians.
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6. Conclusions The results of this study indicate that PTSD and depression are long-term mental health sequelae of the Wenchuan earthquake among its survivors, even after eight years. Different sets of risk factors are associated with symptomalogical PTSD and depression among adult earthquake survivors. Objective exposure is associated with chronic comorbid symptomalogical PTSD and depression, while subjective exposure is associated with long-term depression. These findings may have implications for future post-earthquake mental health programs. Disclosure statement No competing financial interests exist. Contributors JG drafted the manuscript. ZQ, XW, and CL were involved in the design of this study, research instrument development, and data collection. HH was involved the data analysis and revised the manuscript. All authors were involved in writing the manuscript and approve of its final version. Funding This study was supported by National Natural Science Foundation of China (31500912). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Acknowledgments The authors wish to thank Ms. Cordelia Fuller for her careful edit of the paper, and thank all those who helped to collect the data and those who kindly volunteered to participate in the study. The authors further wish to express their deepest condolences to all of the families and individuals who lost family members or relatives in the 2008 Sichuan earthquake disaster. References Bromet, E.J., Atwoli, L., Kawakami, N., Navarro-Mateu, F., Piotrowski, P., King, A.J.,
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