Public health lessons learnt from other disasters involving exposure to toxic substances

This contribution focuses on a special type of disasters termed 'toxic disasters'. Like the other events described in this report, toxic disasters are human-made and profoundly affect the sense of safety people need in order to continue their lives. Such effects are also characteristic of war and natural disasters. Toxic disaster effects also differ from other effects because in many cases they are determined by concerns for the future, anxiety about what might still happen rather that what has actually happened. Human made catastrophes involving toxic exposures with the potential to harm population health can have an even more severe and relentless psychological impact than natural disasters. Nuclear disasters fall into this category. When focusing on nuclear disasters, we know that mental health was the biggest long-term public health problem that ensued from the nuclear accidents of Three Mile Island and Chernobyl, and mental health is again a pressing public health issue after the Fukushima Daiichi accident. Several reviews have concluded that disasters involving radiation exposure, whether real or perceived, have complex and persistent emotional effects, probably because the exposure is invisible and universally dreaded, and can pose a long-term threat to health. The psychosocial consequences of disasters have been studied for more than 100 years. The most common mental health consequences are depression, anxiety, post-traumatic stress disorder, general distress, medically unexplained somatic symptoms (e.g. fatigue, severe headaches, muscle and joint pain) and stigma. The excess morbidity rate of psychiatric disorders in the first year after a disaster ranges from 25-75% depending on the severity of the disaster and on the timing and methodology of the assessment. While the number of dead, injured or hospitalised can be counted, the psychological and social sequelae are harder to quantify - there is no universal unit for indicating the amount of anxiety, depression, social disruption or family hardship that these events produce. Despite the enormous physiological and social cost of toxic disasters, until recently there has been a tendency not to take into account this axis in assessing the adverse effects of these disasters. It is therefore of interest to appraise what can be learnt from toxic disasters in general from the public health perspective in order to enhance the quality of future interventions should a nuclear accident happen in the future. (author)