Psychosocial sequelae of the 1989 Newcastle earthquake: I. Community disaster experiences and psychological morbidity 6 months post-disaster.

A stratified random sample of 3007 Australian adults completed a screening questionnaire 6 months after the 1989 Newcastle earthquake. Information was obtained on initial earthquake experiences and reactions, use of specific services, social support, coping strategies and psychological morbidity. This questionnaire was the first phase of the Quake Impact Study, a longitudinal project investigating the psychosocial impact of the earthquake. Two weighted indices of exposure were developed: a threat index, which measured exposure to injury or the possibility of injury; and a disruption index, which measured experiences of property damage, displacement and other losses. Levels of exposure to threat and disruption events were significant predictors of morbidity on both the General Health Questionnaire and Impact of Event Scale, as were coping style and gender. Effects of exposure to threat and disruption were largely additive, with higher exposure being associated with greater use of support services, higher perceived stressfulness and more severe psychological morbidity. Use of avoidance as a coping strategy, female gender, lower social support and being older were also associated with higher post-disaster psychological distress. It was estimated that 14.8% of the population was exposed to high levels of threat or disruption, of whom approximately 25% experienced moderate to severe psychological distress as a direct result of the disaster. It was further estimated that 18.3% of those exposed to high levels of threat were at risk of developing post-traumatic stress disorder, representing approximately 2% of the city's adult population.