Impaired psychological recovery in the elderly after the Niigata-Chuetsu Earthquake in Japan:a population-based study

Abstract

Background: An earthquake measuring 6.8 on the Richter scale struck the Niigata-Chuetsu region of Japan at 5.56 P.M. on the 23rd of October, 2004. The earthquake was followed by sustained occurrence of numerous aftershocks, which delayed reconstruction of community lifelines. Even one year after the earthquake, 9,160 people were living in temporary housing. Such a devastating earthquake and life after the earthquake in an unfamiliar environment should cause psychological distress, especially among the elderly.

Methods: Psychological distress was measured using the 12-item General Health Questionnaire (GHQ-12) in 2,083 subjects (69% response rate) who were living in transient housing five months after the earthquake. GHQ-12 was scored using the original method, Likert scoring and corrected method. The subjects were asked to assess their psychological status before the earthquake, their psychological status at the most stressful time after the earthquake and their psychological status at five months after the earthquake. Exploratory and confirmatory factor analysis was used to reveal the factor structure of GHQ12. Multiple regression analysis was performed to analyze the relationship between various background factors and GHQ-12 score and its subscale.

Results: GHQ-12 scores were significantly elevated at the most stressful time and they were significantly high even at five months after the earthquake. Factor analysis revealed that a model consisting of two factors (social dysfunction and dysphoria) using corrected GHQ scoring showed a high level of goodness-of-fit. Multiple regression analysis revealed that age of subjects affected GHQ-12 scores. GHQ-12 score as well as its factor 'social dysfunction' scale were increased with increasing age of subjects at five months after the earthquake.

Conclusion: Impaired psychological recovery was observed even at five months after the Niigata-Chuetsu Earthquake in the elderly. The elderly were more affected by matters relating to coping with daily problems.

Figure 1

Time course of GHQ-12 scored by three different methods. GHQ-12 scores were assessed five months after the earthquake, and the subjects were required to assess mental state before the earthquake (Pre), mental state at the most stressful time after the earthquake (Post) and mental state at the time of assessment (Now). Mean and standard deviation values are shown. Differences between scores at the three points of time were analyzed by ANOVA with Scheffe post hoc analysis. A p-value less than 0.01 is indicated by an asterisk (*).

Figure 2

Difference in C-GHQ scores by age. C-GHQ scores before the earthquake (pre-earthquake), at the most stressful time after the earthquake (post-earthquake) and five months after the earthquake (now) are shown as mean and standard deviation values. In each graph, plots from left to right correspond to the six age groups shown in Table 1. The effect of age of subjects on the GHQ-12 scores was analyzed by ANOVA. The p value in each test is shown in the plot.

Figure 3

Differences in lower scale points of each factor by age group of subjects. The relationships between subjects' age and factor I or factor II points of pre-earthquake, post earthquake and now are shown as mean and standard deviation values. In each graph, plots from left to right correspond to the six groups of age shown in Table 1. Trends of GHQ-12 scores with increasing age of subjects were analyzed by the ANOVA. The p value in each test is shown in the plot.