Mental disorders have profound social, cultural, and economic effects throughout the world. Although most psychiatry and psychology texts provide some basic data on the prevalence and treatment of mental disorders, no previous book has ever presented such data with the breadth or depth of the current volume. Reported here are the first results of the WHO World Mental Health (WMH) Survey Initiative, the largest coordinated series of cross-national psychiatric epidemiological surveys ever undertaken. The general population surveys in the WMH series span 17 countries in all parts of the world. In many of these countries the WMH surveys provide the first community epidemiological data ever available on mental disorders in the population. The detailed information on lifetime prevalence, age of onset, course, correlates, and treatment of mental disorders in this volume provides mental health professionals and healthcare policy planners with an unprecedented state-of-the-art reference on the cross-national descriptive epidemiology of mental disorders.