Dr Dan Chisholm is a social scientist with interests and expertise in public health, mental health policy and economics, and health systems research. He is working as a Mental Health Specialist in the Office of the Director, Department of Mental Health and Substance Use, WHO Headquarters Office, Geneva, Switzerland. His main areas of work include development and monitoring of mental health plans and policies, technical assistance to WHO Member States on mental health system strengthening, and analysis of the costs and cost-effectiveness of strategies for reducing the global burden of mental health conditions. He has published widely in these areas over the last twenty years, including as part of the Lancet’s series on global mental health. He also co-edited the mental, neurological and substance use disorders Volume of the third edition of Disease Control Priorities (DCP-3).