Improving a person's economic situation reduces their risks of anxiety and depression, and addressing these common mental illnesses reaps economic benefits by increasing employment and an individual's earnings, according to a new review of research.
In a paper published in the December 11 issue of Science, Matthew Ridley, a researcher at the Massachusetts Institute of Technology, and colleagues examine the accumulating evidence from a wide range of interdisciplinary studies that demonstrate a causal relationship between poverty and mental health.
Understanding the links between poverty and mental health matters can help policymakers design more effective policies to both improve mental health and reduce poverty, said Ridley and the authors — an especially urgent consideration during COVID-19.
"The ongoing pandemic has severe adverse impacts on both poverty and mental health. COVID-19 has disproportionality affected the poor and may have lasting impacts on their economic and mental well-being," said Ridley.
In the absence of support, those living in poverty in many places around the world are getting hit with a "triple disaster" — not only are they navigating the risks of COVID-19, but also the compounding effects of poor psychological health and economic suffering caused by the pandemic.
A Causal Link
Depression and anxiety are the most common mental illnesses, afflicting nearly 3% to 4% of the world's population at any given time and significantly contributing to the global burden of disability. While cost-effective mental health treatments are widely available, many governments invest far less in mental health care compared to physical health services — particularly in low- and middle-income countries.
Once thought to be "diseases of affluence," a growing number of studies leveraging natural and controlled economic experiments involving populations worldwide suggest that people who live below the poverty line are often substantially more likely to be affected by anxiety and depression. Similarly, those afflicted with mental illnesses are much more likely to face greater economic challenges due to a related loss of employment and income, leading to poverty.
However, many of these studies also show that interventions or programs designed to improve mental health and economic condition often positively affect those suffering from poverty or mental illness, respectively. According to Ridley, such findings suggest that the two maladies are not just correlated, but causally related.
Ridley and colleagues write that the most compelling causal evidence for the relationship between poverty, depression and anxiety comes from a wide-ranging set of randomized controlled trials.
Some, like the notable Oregon health insurance experiment published in 2012, which offered largely free health insurance to low-income recipients, reduced rates of depression by nearly 25% in a span of a few months. Other studies demonstrate the impact of cash transfers and other anti-poverty programs have on mental well-being.
"Across many different countries and settings, studies find that the people who received these transfers report much better mental health months or years later than those who didn't," said Ridley.
On the other hand, studies show that people with depression or anxiety who are randomly selected to receive treatments are more likely to be gainfully employed in the following months.
Despite the strong causal evidence these studies reveal, it is still not clear exactly how mental illness leads to poverty, or why poverty causes mental illness and how the two may reinforce one another.
Ridley and the researchers suggest a number of possibilities, including the worries and uncertainties that come with living in poverty, and the effects of poverty on childhood development, for example. Whatever the case, policies that aim to address poverty or mental illness should tackle both issues as one, they say.
According to Ridley, studies from around the world in the past few months have shown very worrying increases in rates of depression, anxiety and stress related to the ongoing COVID-19 pandemic.
"Of course, it is understandable that health concerns and the personal trauma and social isolation that COVID has brought would worsen mental health. But it's also driven by the economic impacts of pandemic. The data show that lower-wage workers are suffering the most financially from the pandemic in countries like the U.S. and India," said Ridley.
"A massive investment in mental health was already long overdue. It has now become critically urgent," said Ridley.