It is estimated that the burden of mental and addictive disorders are among the highest in the world with expected increase over the next decades. However, those estimations are not based on cross-sectional epidemiological surveys, rather, they are mainly based on literature reviews and isolated studies. The WMH Survey Initiative aim is to accurately address the global burden of mental disorders by obtaining accurate cross-sectional information about the prevalences and correlates of mental and behavioral disorders as well as substance abuse, allowing for evaluation of risk factors and study of patterns of service use in order to target appropriate interventions.