People with poor literacy battle more mental health problems worldwide, according to new research from the University of East Anglia.

A new study published today is the first to look at the global picture of literacy and mental health.

Fourteen percent of the world's population still has little or no literacy – and the study finds that they are more likely to suffer mental health issues such as loneliness, depression, and anxiety.

The team, from UEA's Department of Clinical Psychology and Psychological Therapies (CPPT), say their findings disproportionately affect women, who account for two thirds of the world's illiterate.

Despite rising literacy rates over the past 50 years, there are still an estimated 773 million adults globally who can't read or write. Literacy rates are lower in developing countries and those with a history of conflict, and women are disproportionately affected.

We know that people with better literacy tend to have better social outcomes in terms of things like finding employment, being paid well, and being able to afford better food and housing. Not being able to read or write holds a person back throughout their life and they often become trapped in poverty or more likely to commit crime.

We also know that lower literacy is related to poorer health, chronic diseases and shorter life expectancy.

There has been some research examining the potential association between literacy and mental health but this is the first study looking at the issue on a global scale."

Dr Bonnie Teague from UEA's Norwich Medical School

The team reviewed data from 19 studies that measured both literacy and mental health. These studies took place across nine different countries (USA, China, Nepal, Thailand, Iran, India, Ghana, Pakistan, and Brazil) and involved almost two million participants.

Dr Lucy Hunn completed this systematic review as part of her Doctorate in clinical psychology training at UEA. She said: "We used information relating to mental health and literacy to assess the global reported relationship between these two factors.

"What we found is a significant association between literacy and mental health outcomes across multiple countries.

"People with lower literacy had greater mental health difficulties such as anxiety and depression.

"We can't say for sure that poor literacy causes poor mental health, but there is a strong association.

"There may be multiple factors impacting on mental health which also impact literacy – such as poverty or living in an area with a history of conflict. However, what the data does show is that even in these places, you still see worse mental health for those without literacy skills.

"This work highlights the importance of mental health services being aware of and supporting literacy," she added.

Literacy and Mental Health Across the Globe: A Systematic Review is published in the journal Mental Health and Social Inclusion.