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Aim: This study was undertaken 5 months after the 2004 Niigata–Chuetsu earthquake in Japan to assess factors that impacted on psychological distress and its recovery.
Methods: Three thousand and twenty-six adult victims who lived in temporary shelter and in seriously damaged areas were evaluated by questionnaire. The questionnaire queried subject profile, degree of house damage, health status, and psychological distress using a 5-point scale before, immediately and 5 months after the earthquake.
Results: Immediately after the earthquake, 59.3% of the subjects had psychological distress. At 5 months after the earthquake, however, this percentage decreased to 21.8%. The psychological distress immediately after the earthquake was significantly serious in victims who: (i) were female; (ii) felt stronger fear of the earthquake and the aftershocks; (iii) lived at home or office after the earthquake; and (iv) were injured due to the earthquake or suffered from sickness after the earthquake. In contrast, the factors impairing psychological recovery 5 months after the earthquake were as follows: (i) being with unfamiliar member(s) during the night after the earthquake; (ii) serious house damage; (iii) living in temporary shelter or at a relative's home after the earthquake; and (iv) physical illness after the earthquake.
Conclusion: Despite differences between disasters, these results were consistent with those in some previous studies and may be useful for long-term mental care support.
ACCORDING TO A survey in the USA, 13% of all people suffer from natural or human-generated disasters during their lifetime.1 Also, according to the National Comorbidity Survey, 18.9% of male and 15.2% of female individuals experience a natural disaster in their lifetime.2 Therefore, disasters are not rare events.
At 5:56 p.m. on 23 October 2004, a severe earthquake with a magnitude of 6.8 and a maximum tremor intensity level of 7 according to the Japanese 7-stage seismic scale occurred in and around the Chuetsu Area, Niigata Prefecture. Approximately 100 000 people took refuge (49 killed, 4794 injured), approximately 120 000 houses were damaged (including 3185 completely destroyed), and the damage amounted to >¥3 trillion (as of 16 September 2005). Because of the sustained occurrence of aftershocks and delayed reconstruction of community lifelines, 9160 people who lost their houses were still living in temporary shelter as long as 1 year after the earthquake.3
Disasters (e.g. earthquakes, floods, traffic accidents) are traumatic events that many people encounter and may cause various psychological or physical health problems.4 The impact of the devastating earthquake and subsequent life in an unfamiliar environment would cause psychological distress for almost all people affected by the earthquake.5–9 In some people, however, severe mental problems such as depression and/or post-traumatic stress disorder (PTSD), known risk factors for suicidal thinking,10,11 will occur and they may continue to suffer from these mental disorders for a long time.12–14
In the present study we examined the factors that impacted on psychological distress and its recovery after the 2004 Niigata–Chuetsu earthquake in community-based large-scale samples.
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The subjects were 3026 adult victims consisting of all those living in temporary shelter and those living in seriously damaged areas. The latter group was selected on the basis of house damage assessment (complete destruction, partial destruction, minor destruction) and standardizing the sampling frequency by correcting for the population density. Five months after the earthquake, a questionnaire entitled ‘Opinion Survey Concerning Disaster Relief after Niigata–Chuetsu earthquake’ was distributed and collected by door-to-door survey in cooperation with the Red Cross of Japan from mid- to late March, 2005, and responses were collected from 2083 people (1137 male, 946 female) who consented to the survey (return rate: 68.8%). Table 1 shows the age and gender distribution of the subjects. This study protocol was approved by the Ethical Review Board, Niigata University School of Medicine.
Table 1. Subject details
|Age groups (years)||Total||Male||Female|
The questionnaire consisted of 42 questions addressed to various situations during and after the earthquake. Among them, mental health status was assessed on a 5-point self-report scale: (i) very good; (ii) good; (iii) neither good nor poor; (iv) poor; and (v) very poor. The value assigned to each answer (i–v) was regarded as a score of the severity of psychological distress. The subjects were also asked to assess their mental health status before, immediately after the earthquake, and at the time of the survey (i.e. 5 months after the earthquake). Additionally, the following 19 items were selected as factors that may affect psychological distress and its recovery: (1) gender; (2) age; (3) place of residence when the earthquake occurred; (4) occupation; (5) family structure; (6) whether the family was separated by the earthquake or not; (7) whether being on a pension or not; (8) whereabouts at the time of the earthquake; (9) whether being with anyone at the time of the earthquake or not; (10) time until family reunion after the earthquake; (11) behavior after the earthquake; (12) whether being with anyone during the night after the earthquake or not; (13) whereabouts during night-time on the day of the earthquake; (14) fear of the earthquake or aftershocks; (15) degree of house damage; (16) time until first contact with rescue staff; (17) whether using temporary shelter or not; (18) place of living after the earthquake; and (19) whether physically ill or injured after the earthquake or not.
Statistically, comparisons among groups were performed using χ2 test with Bonferroni correction. Also, the factors that impacted on psychological distress and its recovery after the earthquake were determined on multiple logistic regression (with concomitant use of the stepwise method). The score of each group was expressed as mean ± SD, and P < 0.05 was regarded as significant.
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Table 2 presents the changes in subjects with psychological distress before, immediately and 5 months after the earthquake. Of all the subjects, 59.3% reported their mental health status as distressed (reported ‘poor’ or ‘very poor’) immediately after the earthquake. There was a significant difference in the ratio of psychological distress between before and immediately after the earthquake (χ2 = 297.6, P < 0.01). Five months after the earthquake, gradual improvement was observed.
Table 2. Changes in psychological distress
| ||Very good||Good||Neither good nor poor||Poor||Very poor|
| n (%)|| n (%)|| n (%)|| n (%)|| n (%)|
|Before earthquake||916 (46.2)||510 (25.7)||341 (17.2)||160 (8.1)||55 (2.8)|
|Immediately after earthquake||166 (8.4)||207 (10.4)||434 (21.9)||648 (32.7)||528 (26.6)|
|Five months after earthquake||503 (25.0)||592 (29.4)||479 (23.8)||325 (16.2)||112 (5.6)|
Table 3 shows the results of multiple logistic regression of factors that affected psychological distress and its recovery after the earthquake. In this analysis, the degree of psychological distress was used as the dependent variable.
Table 3. Multiple logistic regression with degree of psychological distress as dependent variable
| ||Independent variable||B||SE|| P ||Exp(B)|
|Immediately after earthquake||Female gender||0.410||0.123||0.001||1.508|
|Place of residence (Nagaoka City)||−0.598||0.174||0.001||0.550|
|Place of residence (Koshiji Town)||−0.552||0.221||0.012||0.576|
|Fear of the earthquake||0.812||0.173||<0.001||0.444|
|Fear of the aftershocks||1.170||0.265||<0.001||0.310|
|Living at home after the earthquake||0.924||0.448||0.039||2.518|
|Living at office after the earthquake||0.618||0.171||<0.001||1.855|
|Injury after the earthquake||0.652||0.223||0.004||1.918|
|Physical illness after the earthquake||0.672||0.196||0.001||1.958|
|Five months after earthquake||Being with unfamiliar member(s) during night-time on the day of the earthquake||0.853||0.380||0.025||2.346|
|Serious house damage||0.512||0.079||<0.001||0.596|
|Living at relative's home after the earthquake||0.863||0.287||0.003||2.370|
|Living at temporary shelter after the earthquake||0.493||0.179||0.004||1.637|
|Physical illness after the earthquake||0.669||0.226||0.002||1.951|
The psychological distress immediately after the earthquake was significantly serious in the victims who: (i) were female; (ii) felt stronger fear of the earthquake and the aftershocks; (iii) lived at home or office after the earthquake; and (iv) were injured due to the earthquake or suffered from physical illness after earthquake. In contrast, the factors impairing psychological recovery 5 months after the earthquake were as follows: (i) being with unfamiliar member(s) during night-time on the day of the earthquake; (ii) serious house damage; (iii) living in temporary shelter or a relative's home after the earthquake; and (iv) physical illness after the earthquake.
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With regard to psychological study of disaster victims, to the best of our knowledge there is a paucity of large-scale psychological studies of disaster victims involving subjects selected from the general population of an entire disaster-stricken area in consideration of the severity of damage and population density.15 In the present study, factors that affected psychological distress and its recovery in victims after a devastating earthquake were evaluated in more than 2000 community-based samples. Consequently, we found some factors that impacted on psychological distress immediately and 5 months after the earthquake.
In the present study, factors significantly associated with psychological distress immediately after the earthquake were female gender, fear of the earthquake and aftershocks, living at home or office after the earthquake, and injury or physical illness after the earthquake. Moreover, factors that impaired psychological recovery 5 months after the earthquake were being with unfamiliar member(s) during night-time after the earthquake, serious house damage, living in a temporary shelter or at a relative's home after the earthquake, and physical illness after the earthquake.
Lima et al. examined the relationship between disaster and psychological problems 2 months following the 1987 earthquake in Ecuador and found some risk factors that affected emotional disturbance as follows: (i) not being married; (ii) reporting physical or emotional health problems; and (iii) having ill-defined physical complaints.16 Sharan et al. also indicated that the degree of destruction of house and property was significantly associated with the severity of psychiatric morbidity.17 Recently, Chen et al. investigated the psychiatric morbidity and post-traumatic symptoms among survivors in the early stage following the 1999 earthquake in Taiwan and found that factors significantly associated with high psychiatric morbidity were female gender, serious destruction of property and housing, and personality characteristics of nervousness and obsessiveness.18 More recently, Ohta et al., who provided support for the mental health of evacuees from the volcanic eruption of Mt Unzen for 44 months indicated that recovery from psychological distress was more difficult in middle-aged and older evacuees than in younger evacuees.19
There have been a number of studies on PTSD. For example, women are more likely than men to have PTSD after natural disasters,20,21 and low social support is associated with a higher likelihood of PTSD.22–25 A greater degree of exposure to a disaster is also consistently associated with the likelihood of PTSD.25–27 It is very interesting that the same factors are associated with PTSD and psychological distress after a disaster, despite considerable differences in severities and pathologies between them.
According to our results, some factors such as female gender, serious house damage, and injury or physical illness after the earthquake were indicated to affect psychological distress after the earthquake. These are consistent with previous reports mentioned here. Interestingly, the present results showed that both history of living in a temporary shelter or at a relative's home after the earthquake and ‘fear of the earthquake and the aftershocks’ affected psychological distress. The former factors were not reported in previous studies and the latter may be in line with the report by Chen et al., indicating that ‘personality characteristics of nervousness’ affected psychological distress after the earthquake.18 Further studies are needed to evaluate those matters.
Shinfuku, who had the rare experience as a medical doctor of being both a victim and an observer of a major disaster in the Hanshin–Awaji earthquake, indicated that good physical health depended greatly on good mental health, and that good mental health depended on a sound social environment, including housing and community.28 Moreover, he stressed the importance of long-term and wide-ranging programs for victims, including housing, employment, and financial support.28 Our results confirm his indications.
Several potential limitations should be taken into account in the interpretation of this study. First, the questionnaire used to assess mental health status included retrospective evaluation about ‘before’ and ‘immediately after’ the earthquake. There might be some problems about the accuracy of scores that were made retrospectively. Second, in Japan the female population is usually larger than that of men in older age, but not in the present study (male > female). This discrepancy must have been due to sampling bias, because there is a similar tendency to Japan in Nagaoka City, which also experienced severe damage from this earthquake (male, 137 906 < female, 144 308; 2007 data). Therefore, it is possible that these results may not reflect other areas in Japan, although we could not find the cause of the discrepancy.
We hope that our results will be used effectively by administrative organizations of countries that are frequently stricken by natural disasters including Japan.