World Mental Health (WMH) Survey Initiative Series

The World Mental Health (WMH) Survey Initiative is a coordinated series of general population surveys of mental, substance use, and behavioral disorders conducted in countries across all World Health Organization (WHO) regions. Initiated by the World Health Organization’s Assessment, Classification, and Epidemiology (ACE) Group, the initiative began in 2001 with the National Comorbidity Survey Replication (NCS-R) in the United States.

All WMH surveys used the WMH version of the World Health Organization Composite International Diagnostic Interview (WMH-CIDI), a fully structured, lay administered diagnostic instrument. Disorders are assessed using DSM-IV and ICD-10 criteria, with standardized questions on symptoms, onset, course, impairment, and treatment. A rigorous translation, back-translation, and harmonization protocol was used to guarantee valid comparisons of mental and substance use disorders across diverse countries and regions.

The WMH Survey Initiative was designed to fill major gaps in global mental health data. Earlier estimates of the burden of mental and addictive disorders relied largely on literature reviews and isolated studies. In contrast, WMH surveys provide rigorously implemented, nationally or regionally representative data to:

• Estimate the prevalence and distribution of mental, substance use, and behavioral disorders
• Identify risk and protective factors to inform prevention and intervention strategies
• Describe patterns of service use, unmet need, and barriers to care
• Improve estimates of the global burden of disease attributable to mental disorders for public health planning

This ICPSR series includes WMH surveys conducted between 2001 and 2019 in: Argentina, Brazil, Bulgaria (two national cross-sectional surveys ten years apart), Colombia (a national survey and a separate urban survey in Medellín), France, Germany, Iraq, Italy, Japan, Lebanon, Mexico, New Zealand, Nigeria, Northern Ireland, Peru, Poland (two cross-sectional surveys eight years apart), Portugal, Romania, South Africa, Spain (two surveys, one national and one regional in Murcia), Ukraine, and the United States. Public-use files in this series provide harmonized WMH-CIDI data suitable for cross national and within country analyses. Study-level documentation and related materials are included to support secondary analyses by researchers, policymakers, and students.

For a complete description of the WMH CIDI instrument and its development, see: Kessler, R.C., & Üstün, T.B. (2004). The World Mental Health (WMH) Survey Initiative Version of the World Health Organization (WHO) Composite International Diagnostic Interview (CIDI). International Journal of Methods in Psychiatric Research, 13(2), 93–121. For information on WMH reports, see the World Mental Health Survey Initiative website. 

Note that WMH surveys conducted after 2019 used an updated DSM-5/ICD-11 version of the CIDI ("CIDI-5"). Five countries have completed CIDI-5 data collection, and many more are in process or being planned. The WMH consortium is developing a new secure data enclave to allow public access to these data – information about the enclave and on-going WMH work will be posted to the WMH website once plans are finalized.