Mental illness is one of the great invisible burdens on developing societies, accounting for four of the 10 leading causes of disability worldwide. In emergencies, the problem is even greater, as the number of people suffering from severe mental disorders increases and those with pre-existing mental illnesses are exposed to new levels of stress. International Medical Corps understands the devastating effect that mental illness has on the world's poorest nations. As part of its holistic approach to health, International Medical Corps incorporates mental health and well-being into its programs to address the psychosocial needs of disaster survivors and help those with pre-existing mental disorders. A leader in mental health care in emergency settings, we have implemented mental health programs throughout Asia, Africa, Latin America, and the Middle East, as well as in the United States following Hurricane Katrina.