Post-traumatic Stress Disorder among adult survivors of the Wenchuan Earthquake in China: A repeated cross-sectional study

Highlights

• A four-year repeated cross-sectional survey data was used to examine PTSD symptoms.

• The prevalence of PTSD reached 58.2% at two months, and then steadily declined.

• Demographic and health related variables affected PTSD during the early period.

• Depression has a long-term impact on survivors’ PTSD.

Abstract

The objective of the study was to examine trends in the prevalence of Posttraumatic Stress Disorder (PTSD) in Wenchuan, China, over the four-year period following its 2008 earthquake, and to explore the risk factors related to current PTSD. Chi-square analysis and multivariate logistic regression analysis were used to assess PTSD morbidity and identify associated risk factors. The results indicated that the prevalence of PTSD was 58.2% at two months, 22.10% at 8 months, 19.8% at 14 months, 19.0% at 26 months, and 8.0% at about 44 months after the earthquake. Female gender, being married, low education, non-drinking, and poor self-perceived health status were significantly associated with PTSD during the early period following the earthquake. Depression was significantly associated with survivors’ PTSD throughout the study period.

Introduction

Earthquakes are common natural disasters, and on average 939 earthquakes of a magnitude between 5 and 8 on the Richter scale occur around the world each year (Naeem et al., 2011). Compared to other types of natural disasters, earthquakes strike more quickly, often without warning, are more uncontrollable, and affect larger populations; they leave injury, death, and destruction in their wake (Altindag, Ozen, & Sir, 2005). Compared to disasters occurring in developed countries, those that occur in developing countries tend to lead to more severe consequences, including mental health consequences, among affected populations, in part because of a context of lower availability of resources in general, and of mental health treatment resources in particular (Norris et al., 2002). However, due to low levels of funding support and public attention, relatively few post-earthquake research studies have been conducted in developing countries (Tural et al., 2004). Neria et al. reviewed 116 studies of the mental health consequences of natural disasters, of which seventy six were from developed countries and only 40 from developing countries (Neria, Nandi, & Galea, 2008). Clearly, then, there is a need for more research on the short- and long-term mental health consequences of severe earthquake in developing countries.

On May 12, 2008, a magnitude 8.0 earthquake struck the area around Wenchuan, in the north western part of China's Sichuan province. It left 69,227 people dead, 374,643 injured, 17,923 missing, and millions homeless (SCIOC, 2008). Kun et al. reported a PTSD prevalence of 45.5% in a heavily damaged county in the earthquake area 3 months after the earthquake (Kun et al., 2009). PTSD prevalence rates of 26.3% and 52.2% were reported in two independent studies one year after the earthquake (Liu et al., 2012, Zhang et al., 2011). Studies of the impact of the Wenchuan earthquake on the mental health of the 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 risks factors associated with PTSD among adults (Kun et al., 2009, Wang et al., 2009, Zhang and Ho, 2011, Zhang et al., 2011). The long-term sequelae of earthquakes tend to receive little research attention. A recent systematic review (Xiao et al., 2011) found that the number of published journal articles on the health consequences of an earthquake tend to drop dramatically 2 years after its occurrence. To the best of our knowledge, very few studies to date have focused on the adult survivors of the Wenchuan earthquake, and none have examined the long-term mental health effects of this disaster.

Though a large number of studies have investigated the development of PTSD and changes in PTSD symptom severity over time, these studies had some limitations which should be noted. First, most of these studies have been conducted among individuals exposed to combat (Bonanno et al., 2012), or bereavement (Bonanno et al., 2002). Little is known about long-term trends in PTSD among earthquake survivors. Second, the picture of post-event psychological sequelae emerging from these studies is inconsistent and often confusing. One study found that general psychological morbidity tends to decline over time, and to stabilize at about 12 months after an earthquake, and that PTSD symptom levels tend to stabilize after about 18 months (Carr et al., 1997). A longitudinal study of earthquake-affected communities in northern China, however, reported a higher prevalence of psychopathology at nine months than at three months post-event (Wang et al., 2000). Moreover, findings concerning the risk factors for post-disaster psychological problems have also been inconsistent. Two meta-analytic studies (Brewin et al., 2000, Ozer et al., 2003) found that although quite a few risk factors have been identified, most have only shown small effect sizes, and little predictive value for predicting who develops PTSD (Brewin, 2005, Brewin et al., 2000). Finally, although rigorous methods have sometimes been used, a widely divergent array of questionnaires, surveys, interviews, and psychiatric classification systems have been employed, limiting comparability across studies and likely contributing to the wide variation and inconsistencies of the findings of earthquake research (Tural et al., 2004).

The objectives of the present study were to estimate the prevalence of probable PTSD at different time points following an earthquake, and to identify the factors associated with PTSD, using data from a repeated cross-sectional survey conducted in China.