Post-traumatic stress disorder (PTSD) is a severe and frequently chronic physical and emotional response to traumatic and stressful events. Events of this type include wartime, terrorism, criminal violence and other acts of violence, plane crashes and other serious transportation accidents, and natural disasters such as hurricanes, floods, fires, landslides, and earthquakes. PTSD is a well-established conceptualization of people's psychological reactions to threat-inducing experiences, one that has substantive negative effects, including increased morbidity, poor quality of life, and increased uptake of addictive substances, as well as higher medical and social costs. PTSD is the most commonly assessed outcome of disasters, with its symptomology tending to decrease over time. In a general sense, its symptomology includes a person's reliving a traumatic event, avoiding things that are reminiscent ...