By: Alanna Shaikh, MPH on April 19, 2016Global health hasn’t historically engaged much with mental health. It tended to be seen as a luxury, or an issue to be taken on only once the important issues were addressed. Even suicide didn’t get a lot of attention. That’s been changing in the last few years. This is in part because mental illnesses are now being seen as biological diseases with physiological causes. It’s also the result of research demonstrating just how disabling and prevalent mental illness actually is.A new publication in The Lancet, “Scaling-up treatment of depression and anxiety: a global return on investment analysis,” takes that research to a more complex level, using an economic approach to analyze mental illness. The report identifies the economic impact of the disability caused by mental illness, and then analyzes it in comparison to the cost of treatment and the resulting increase in productivity. The results are interesting – the report finds that overall, for every dollar spent treating mental illness in people over the age of fifteen, $2.30-$3.00 in productivity is created.The scale of global mental illness is tremendousThe report focuses specifically on depression and anxiety disorders, as they’re the most common mental illnesses. The global prevalence rate for anxiety disorders is 7.3%. For depression it is 3.2% for men and 5.5% for women. At the same time, very little funding is invested into treatment for these disorders. In lower-income countries, only $2 per person is spent on mental health care.According to the study, across the 36 largest countries in the world, at current treatment levels, it is projected that more than 12 billion days of lost productivity are attributable to depression and anxiety disorders every year, at an estimated cost of $925 billion. If we assume that those numbers can be generalized to the whole planet, the global cost in lost productivity is $1.15 trillion per year. These 36 countries span all six of WHO’s major regions and account for 80% of the world’s population and 80% of the global burden of depression and anxiety disorders. They’re a good basis to generalize from.In those same 36 countries, we could scale-up treatment over the next fifteen years at a cost of $91 billion for depression and $56 billion for anxiety disorders. This would bring a benefit of $260 billion in productivity for depression treatment and $50 billion for anxiety treatment. Impressively, this comes from increasing treatment numbers by a fairly minimal amount, aiming for “A gradual, linear increase in treatment coverage to a third of all cases in low-income countries and to more than half of cases in high-income countries.” The benefit was calculated by comparing the GDP at current levels to the projected GDP at the increased treatment levels.The individual costs of treatment for depression and anxiety are low, the study reminds us. “… for depression treatment, the average annual cost during 15 years of scaled-up investment is $.08 per person in low-income countries, $.34 in lower middle-income countries, $1.12 in upper middle-income countries and $3.89 in high-income countries. Per person costs for anxiety disorders are nearly half that of depression.”The study aimed to be as pragmatic as possible, according to the authors, and therefore focused on identifying benefits which could be easily quantified for existing data. One major benefit that the authors did not quantify is treatment for maternal depression and its impact on children. It is well known that maternal depression harms children. Reducing rates of maternal depression will support health in children. There is no available data that could be used to quantity that result, though, so it was omitted.The study is not without weaknesses, many of which are mentioned explicitly in the article. For example, they point out that the economic benefit of treating mental illness is every dependent on paid participation in the labor force as a result of treatment. In countries where little work is available, or that work is poorly paid, this result will be unlikely.In addition, for the economic benefits of treatment to be recognized, quality mental health care has to actually exist to be funded. In far too many regions, mental health care is scarce or non-existent. What does exist tends not to be of high quality. In order to reach the point of seeing these kinds of benefits from mental health care, we’ll need an initial investment of funds to develop mental health services.What the report doesn’t sayThe fact that mental health is a good investment doesn’t make it affordable for all countries. As everyone who’s ever wished they could afford health insurance is aware, knowing that something would bring economic benefit in the long run doesn’t mean you have the money in the short run.One sentence takeawayInvesting in mental health would bring major benefits in both economic productivity and human quality of life.