摘要:Objectives. We assessed the levels and correlates of posttraumatic stress reactivity (PTSR) of more than 20000 adult tsunami survivors by analyzing survey data from coastal Aceh and North Sumatra, Indonesia. Methods. A population-representative sample of individuals interviewed before the tsunami was traced in 2005 to 2006. We constructed 2 scales measuring PTSR by using 7 symptom items from the Post Traumatic Stress Disorder (PTSD) Checklist–Civilian Version. One scale measured PTSR at the time of interview, and the other measured PTSR at the point of maximum intensity since the disaster. Results. PTSR scores were highest for respondents from heavily damaged areas. In all areas, scores declined over time. Gender and age were significant predictors of PTSR; markers of socioeconomic status before the tsunami were not. Exposure to traumatic events, loss of kin, and property damage were significantly associated with higher PTSR scores. Conclusions. The tsunami produced posttraumatic stress reactions across a wide region of Aceh and North Sumatra. Public health will be enhanced by the provision of counseling services that reach not only people directly affected by the tsunami but also those living beyond the area of immediate impact. The tsunami associated with the December 26, 2004, Sumatra–Andaman earthquake killed some 250000 people along the coastlines of the Indian Ocean. Indonesia was the country most devastated by the tsunami. Some 130000 Indonesians died, and more than 500000 were displaced. 1 Survivors experienced stresses known to adversely affect mental health, including fear of dying, exposure to dead bodies, loss of loved ones, community disruption, and physical and economic hardship. 2 , 3 We evaluated posttraumatic stress reactivity (PTSR) among adult tsunami survivors in Aceh and North Sumatra, the Indonesian provinces where damage was concentrated. Our study sample, unlike most studies of mental health after a disaster, was representative of the predisaster population living in areas directly affected by the tsunami, as well as those living in similar areas not directly affected. Respondents had been interviewed in February 2004 before the tsunami as part of the National Socioeconomic Survey (SUSENAS), an annual population-based cross-sectional survey conducted by Statistics Indonesia. The SUSENAS survey was representative at the district level and based on a stratified multistage cluster design. With assistance from Statistics Indonesia, we fielded the first wave of the Study of the Tsunami Aftermath and Recovery (STAR) between May 2005 and July 2006. We sought to recontact 39 500 individuals originally interviewed in 2004 in 585 survey communities. We focused on PTSR, the most commonly identified psychological problem among adult survivors of disasters. 2 We had 3 primary objectives: (1) to describe the course of reactions over time, (2) to examine variation associated with degree of damage in the community in which the respondent was living before the tsunami, and (3) to assess the correlation of PTSR to pretsunami characteristics, with exposure to traumatic events, loss of family and friends, and property damage as a result of the tsunami. Because our sample included respondents from communities spanning a continuum of damage, the results provided a comparison of mental health after a disaster in heavily damaged areas against mental health in areas that were not directly affected by the tsunami. We used high-resolution remotely sensed imagery to quantify destruction in the aftermath of a disaster and thereby illustrate the potential value of combining remotely sensed imagery with survey data in public health research. Because we will be collecting several additional waves of data from the same respondents, the results presented here introduce a longitudinal study that will track the evolution of mental health during disaster recovery and rebuilding. This is important because there is very little scientific evidence on mental health trajectories after such events. 4