Social psychiatry is a multidisciplinary field analyzing mechanisms of mental health issues comprehensively to contribute to society using the findings. Those findings include biological, psychological, and social aspects and they are based on psychiatry and connected with a wide variety of academic fields, including psychology, sociology, law, economics, and religious studies. Epidemiological research in psychiatry is a field of study in patients with psychiatric disorder attempting to investigate causes, to develop clinical applications of the results, and to determine applications to health services plans for individuals and/or communities. They are both foundation for understanding biopsychosocial view in psychiatry but not many comprehensive volumes covering the topic were not available until now. This book is thus a unique, comprehensive reference with evidence-based approach to provide concise summary of researches for such as schizophrenia, affective disorders, psychiatric disorders in the general practice setting, and disaster psychiatry, especially for the case of atomic bomb diseases. The studies were mostly carried out in the region of Nagasaki, the prefecture experienced a nuclear attack at the time of World War II. Psychiatric findings in mental health problems among atomic bomb survivors and sufferers in Nagasaki has been established and Nagasaki is the only area that fulfills the conditions of the subject of the study of psychiatric epidemiology and social psychiatry which is going to be described in this book. This book provides a valuable resource not only for physicians and researchers in the field of psychiatry and mental health but for people who work for mental health welfare department.