Brain and other nervous system disorders across the lifespan - global challenges and opportunities.

This is an exciting time for scientific discovery that aims to reduce the frequency and impact of neurological, mental health and substance-use disorders. As it became increasingly clear that low- and middle-income countries have a disproportionate share of these disorders, and that many of the problems are best addressed by indigenous researchers who can seek context-sensitive solutions, the US National Institutes of Health and other research funders began to invest more in low- and middle-income country-focused research and research capacity-building to confront this significant public health challenge. In an effort to identify existing information, knowledge gaps, and emerging research and research capacity-building opportunities that are particularly relevant to low- and middle-income countries, in February 2014 the Center for Global Health Studies at the National Institutes of Health Fogarty International Center held a workshop to explore these issues with scientific experts from low- and middle-income countries and the United States. This evolved into the preparation of the Reviews in this supplement, which is designed to highlight opportunities and challenges associated with topical areas in brain-disorders research over the coming decade. This Introduction highlights some of the over-arching and intersecting priorities for addressing causes, prevention, treatment and rehabilitation as well as best practices to promote overall nervous system health. We review some brain disorders in low- and middle-income countries, while the Reviews describe relevant issues and the epidemiology of particular conditions in greater depth.