Do people fall into poverty because of mental illness, or do people fall into mental illness because of poverty? It’s both.

Poverty and mental illness are not only related, but also causal. This is the conclusion of researchers from Amsterdam UMC, the University of Edinburgh and the University of Modena. Their study shows that while certain mental health problems can hinder economic stability, poverty is also one of the causes of mental health problems. The study was published today in Human behavior in nature.

“This study shows that certain mental health problems can destabilize an individual’s economic situation, but conversely, we know that poverty can lead to mental health problems,” says Marco Box, a psychiatrist at UMC Amsterdam.

Previous studies have shown a strong correlation between poverty and mental illness, but it has proven difficult to separate cause and effect. The impact of mental illness can affect an individual’s financial situation, for example through poor job performance or higher medical costs. But difficult financial situations can also lead to psychological problems.

Complex relationship

The researchers used data from the UK Biobank and the International Psychiatric Genomics Consortium.

“We found that schizophrenia and ADHD are caused by poverty, and conversely, poverty causes major depressive disorder and schizophrenia. In fact, poverty reduces the risk of anorexia nervosa,” Box says.

First, a measure of poverty was determined based on household income, occupational income, and social deprivation. The researchers then used the participants’ genetic information to uncover associations using a special technique called Mendelian randomization, a method of determining the effect of risk factors on disease by measuring common genetic variations for a particular trait.

“We were able to capture common aspects of poverty across individuals, households and neighbourhoods, which allowed us to more precisely pinpoint the causal effects of poverty on mental illness,” says David Hill, a statistical geneticist at the University of Edinburgh.

vicious circle

The findings from this study have implications for policies and approaches to both poverty and mental illness: by recognising the mutual impact of poverty and mental health, policymakers can develop more effective interventions aimed at breaking the vicious cycle of poverty and mental health problems.

“This study provides strong evidence that social factors such as poverty need to be taken into account when examining the development of mental illness,” Box said.

“Our results suggest that reducing inequalities could lead to significant improvements in population mental health,” added Mattia Marchi, a psychiatrist at the University of Modena.

“There is often confusion about using genetic data to investigate the relationship between poverty and mental illness. We emphasize that this does not mean that poverty is genetic. On the contrary, genetic data allow us to identify poverty as a modifiable environmental factor on mental health,” concludes Box.