Berg, B. van den, Grievink, L., IJzermans, J., Lebret, E

INTRODUCTION Many studies have examined the health problems among survivors of disasters, showing that the most frequently reported symptoms after disasters are mental health problems, such as posttraumatic stress symptoms, depression, and anxiety (1, 2). In the last decade, the Netherlands was struck by a few national disasters. On October 4, 1992, an El Al Boeing 747 airplane crashed into two apartment buildings in an Amsterdam suburb. Six years after the airplane crash, a study of the health effects of the crash was conducted. This study showed that, in addition to mental health problems, physical symptoms were very prevalent among the survivors of the plane crash (3, 4). On May 13, 2000, a fireworks depot exploded in a residential area of the city of Enschede. The explosions and subsequent fire killed 22 people and injured over 900 people, and about 500 homes were severely damaged or destroyed. The Dutch government declared this a national disaster, and the Ministry of Health, Welfare, and Sports decided to launch a study into the health effects of this disaster. This study showed that a substantial proportion of those who were affected by the fireworks disaster suffered from physical symptoms, such as headache, fatigue, and pain in the stomach, chest, joints, and muscles (5, 6). These symptoms are often labeled as medically unexplained physical symptoms (MUPS), but other labels, such as psychosomatic symptoms or functional somatic syndromes, have been given as well (7). Survivors of disasters may attribute these physical symptoms to (suspected) exposure to toxic substances, and this may lead to social unrest and amplification of the health problems (8, 9). For example, after the Bijlmermeer airplane crash in Amsterdam, many survivors reported health symptoms that they attributed to possible toxic exposures, such as depleted uranium (3). General practitioners, however, associated only a small proportion (about 20 percent) of the most frequently reported symptoms with a diagnosis, and thus the majority of symptoms were unexplained (4). In the nontraumatized general population, MUPS are also very common, with reported prevalence rates ranging from 5 to 35 percent (10, 11). The majority of these symptoms cannot be explained by a medical diagnosis; general population studies have shown that the etiology of 30–75 percent of such symptoms as headache, fatigue, and stomachache is unknown (10, 12, 13). After disasters, the prevalence rates of MUPS seem to increase. However, since many but not all survivors develop these symptoms, the question arises as to which factors predict who will or will not develop MUPS. Mayou and Farmer (14) divided risk factors into three categories: predisposing, precipitating, and perpetuating factors (which we call the ‘‘3-P model’’). Predisposing factors are factors that already exist before the disaster took place, such as certain demographic characteristics and personality factors. Precipitating factors are directly related to the disaster, for example, injury, relocation, fear, and loss of property. These factors might increase the proportion of survivors that