Air pollution linked to more severe mental illness

A study has argued that exposure to air pollution is linked to an increased severity of mental illness, including significant rises in depression and anxiety.

Involving 13,000 people in London, the University of Bristol research found that a relatively small increase in exposure to nitrogen dioxide led to a 32 per cent increase in the risk of needing community-based treatment and an 18 per cent increase in the risk of being admitted to hospital.

The researchers said the findings were likely to apply to most cities in developed nations, and cutting air pollution could benefit millions of people.

The researchers calculated that a small reduction in one pollutant alone could reduce illness and save the NHS tens of millions a year. Published in the British Journal of Psychiatry, the study tracked patients in south London from their first contact with mental health services and used high-resolution estimates of air pollution at their homes.

Recent research has shown that small increases in air pollution are linked to significant rises in depression and anxiety. It has also linked dirty air to increased suicides and indicated that growing up in polluted places increases the risk of mental disorders.

The study was not designed to prove a causal link between air pollution and the severity of mental illness, but the link is ‘biologically plausible’, the researchers said, as air pollutants are known to have potent inflammatory properties and inflammation is believed to be a factor in psychotic and mood disorders.