Mental disorders such as depression and anxiety are highly prevalent – 15% of the working-age population is affected at any given time. They are also extensively undertreated; globally around 56% of people with depression do not receive appropriate treatment. These disorders contribute significantly to reduced productivity, sickness absences, disability and unemployment, and the total costs of mental ill-health are estimated at 3.5 – 4% of GDP in OECD countries. A particular prevention priority in the area of mental health concerns suicide, which accounted for an estimated 800 000 deaths in 2018 (WHO, 2019[18]). Despite the enormous burden that mental ill-health imposes on individuals, their families, society, health systems and the economy, mental health care remains a neglected area of health policy in too many countries (Hewlett and Moran, 2014[19]). The inclusion of mental health and substance abuse in the Sustainable Development Agenda is likely to have a positive impact on communities and countries, stressing the importance of the promotion of mental health and well-being, and the prevention and treatment of substance abuse.