Diesel pollution raises risk of mental illness for children in cities

CHILDREN who live in cities are much more likely than those in the countryside to develop mental illness, research suggests – with pollution from diesel engines the biggest contributor.

City children aged 13 to 18 were found to have a 70 per cent greater chance of developing psychotic symptoms which can lead to schizophrenia than their rural peers. These symptoms include hallucinations such as hearing voices, believing that they are being spied on and followed, or thinking their food is being poisoned.

Around one in three of all children experiences such symptoms. But those growing up in polluted city areas were much more likely to. Transport, particularly fumes from diesel engines, is one of the biggest contributors to air pollution by nitrogen oxides. These gases were found to be linked closely to the odds of having psychotic symptoms.

Researchers from the Institute of Psychiatry and King’s College London studied more than 2,063 children born in England and Wales.

Using a complex computer model they calculated the levels of pollution in 20m by 20m grid points for nitrogen oxides and particulate matter – a mixture of extremely small particles and liquid droplets suspended in the air.

Tracking adolescents’ home addresses and other relevant locations allowed researchers to estimate their exposure to the major pollutants, the study published in the journal JAMA Psychiatry reported.

The link between air pollution and psychotic symptoms held even when other factors were taken into consideration, such as socio-economic background, levels of crime and family psychiatric history, and history of smoking and substance abuse.

Lead author Dr Joanne Newbury of the Institute of Psy-

‘More common in urban areas’

chiatry said: ‘ We found that adolescent psychotic experiences were more common in urban areas.

‘While the study could not show pollutants caused adolescents to have psychotic experiences, our findings suggest that air pollution could be a contributing factor in the link between city living and psychotic experiences.

‘ For example, teenagers exposed to the highest levels of [nitrogen oxides] had 72 per cent greater odds for psychotic experiences compared to those with lower exposure.’

In an urban area this meant for every 12 who reported a psychotic experience, there were 20 who did not.

In rural areas, the ratio was seven to 20.