The prevention, care, and rehabilitation of mental disorders are a growing public health problem globally. Addressing the increasing public health burden of mental disorders worldwide requires an understanding of the prevalence, associated disability, and treatment gap associated with these disorders. Community-based psychiatric epidemiological studies provide insights into the magnitude of the burden. Estimates of the prevalence of specific mental disorders in numerous countries globally have been established using either structured or semi-structured interview schedules linked to current diagnostic criteria that have improved the reliability and validity of psychiatric diagnoses. The World Mental Health (WMH) surveys and the International Consortium of Psychiatric Epidemiology are cross-national initiatives that have demonstrated that mental disorders are highly prevalent throughout the world. Neuropsychiatric conditions account for a disproportionate amount of burden of disease, although they result in few direct deaths.