Many of us know someone who has suffered from depression. Yet the continuing stigma associated with mental health problems in many parts of the world, as well as competing priorities in others, mean that the scale of the problem and its impact often lie just beneath the surface. While the world remains riven by multiple violent conflicts and other health concerns, including the Ebola crisis, high rates of depression continue to put growing pressure on workplaces and government health budgets around the world.

Around 350m people live with depression globally, according to the World Health Organisation (WHO); the WHO's 2008 World Mental Health Survey of 17 countries found that around one in 20 people on average reported an episode of depression in the previous year. Major Depressive Disorder (MDD) accounted for 8.2% of global years lived with disability (YLD), making it the second leading cause of YLDs, according to the 2010 Global Burden of Disease study. The disease tends to take hold of its victims when they are young, and women are often disproportionately affected, in many cases after childbirth, leading to further collateral damage as it impacts the growth and development of a new generation.

Wide-ranging economic and social impacts

The economic and social effects of high levels of global depression are wide-ranging. In its most serious form, depression leads to a dramatic forestalling of human potential: there are more than 800,000 suicides per year, according to the WHO's first global report on suicide prevention. People with severe mental illnesses (including acute depression) have a life expectancy that is 20 years shorter, on average, than that of the general population.

Moreover, depression has a major impact on people during their most productive years. The OECD says that some 5% of the working-age population is affected by a severe mental health condition and a further 15% by a more common one such as depression or anxiety, and that the direct and indirect costs of mental health problems can be in excess of 4% of GDP. In the US, the Centers for Disease Control and Prevention (CDC) say that around 80% of people with depression report some level of functional impairment due to their condition and 27% report serious difficulties in work and home life. The disease is estimated to cause 200m lost workdays each year in the US, costing employers between $17bn and $44bn annually.

Reliable treatments for depression exist, including antidepressant medications, cognitive behavioural therapy (CBT) and other forms of psychotherapy. Clinical trials in resource-stretched developing countries such as Uganda and India have shown them to be as effective as in mature economies where they are more widely used. Yet, according to the WHO, fewer than half of those affected globally, and in some countries fewer than 10%, are receiving treatment.

Focus on prevention and funding

Meanwhile, some policymakers are increasingly advocating a stronger focus on depression prevention, including school-based programmes emphasising problem-solving, cognitive and social skills for children as well as health and well-being programmes in the workplace and for elderly people.

As the threat to public health from high rates of depression continues to rise, more education about depression in places where it is still stigmatised is vital, as is improved funding for treatment. A World Health Assembly resolution in May 2012 advocated a more coordinated response to mental disorders at the country level. This call is gradually making its way onto the political agenda, as evidenced by UK Deputy Prime Minister Nick Clegg’s recent announcement that the UK government will commit £120m in funding to reduce waiting times for mental health treatment. The aim is to put treatment for mental health conditions on a level with treatment for physical health conditions from 2015.

The impact of depression has been underestimated for too long. Governments and global public health officials will have their work cut out for them.

The socio-economic impact of depression will be discussed at an upcoming Economist conference, The Global Crisis of Depression.

Recent research on mental health by The Economist Intelligence Unit includes a major benchmarking study, called the Mental Health Integration Index, that compares the level of effort in 30 European countries on indicators associated with integrating individuals suffering from mental illness into society.

The views and opinions expressed in this article are those of the authors and do not necessarily reflect the views of The Economist Intelligence Unit Limited (EIU) or any other member of The Economist Group. The Economist Group (including the EIU) cannot accept any responsibility or liability for reliance by any person on this article or any of the information, opinions or conclusions set out in the article.