Teenagers who live in cities plagued by high air pollution are more likely to report hearing voices, suffer from paranoia, and other psychotic experiences, according to groundbreaking study.

Researchers from King’s College London (KCL) said that while they could not prove dirty air was causing the episodes, they had factored out other potential causes such as crime, deprivation, inherited mental illness, smoking, drinking and drug use.

Air pollution could plausibly cause mental health conditions by carrying heavy metal particles into the lungs and body, or by causing inflammation, as the brain is rapidly developing in childhood and adolescence.

The researchers cautioned that more work was needed to verify a causal link – but likened their findings to the first investigations into the relationship between smoking and lung cancer.

They were unable to rule out the possibility the phenomenon may be driven by some other characteristic of life in more air-polluted areas which was not accounted for in the study, such as louder traffic noise, which can disrupt sleep and cause stress.

It is accepted that people living in cities have higher rates of psychosis, but the reasons for this are poorly understood.

The most polluted towns and cities in the UK Show all 25 1 /25 The most polluted towns and cities in the UK The most polluted towns and cities in the UK 25. Middlesbrough 11 micrograms per cubic metre. A report from the World Health Organisation has given figures for fine-particle air pollution across the world. Here follow the 25 most polluted towns and cities in the UK The most polluted towns and cities in the UK 24. Derry 11 micrograms per cubic metre Getty The most polluted towns and cities in the UK 23. Hull 11 micrograms per cubic metre (estimate) Getty The most polluted towns and cities in the UK 22. Coventry 11 micrograms per cubic metre Getty The most polluted towns and cities in the UK 21. London 11 micrograms per cubic metre PA The most polluted towns and cities in the UK 20. Stoke-On-Trent 12 micrograms per cubic metre Getty The most polluted towns and cities in the UK 19. Sheffield 12 micrograms per cubic metre (estimate) Getty The most polluted towns and cities in the UK 18. Sandy, Bedfordshire 12 micrograms per cubic metre Google The most polluted towns and cities in the UK 17. Royal Leamington Spa 12 micrograms per cubic metre Getty The most polluted towns and cities in the UK 16. Prestonpans 12 micrograms per cubic metre Richard Webb The most polluted towns and cities in the UK 15. York 12 micrograms per cubic metre Getty The most polluted towns and cities in the UK 14. Plymouth 12 micrograms per cubic metre Getty The most polluted towns and cities in the UK 13. Nottingham 12 micrograms per cubic metre Getty The most polluted towns and cities in the UK 12. Eccles 12 micrograms per cubic metre (estimate) Rept0n1x The most polluted towns and cities in the UK 11. Grays 12 micrograms per cubic metre (estimate) Getty The most polluted towns and cities in the UK 10. Liverpool 12 micrograms per cubic metre Getty The most polluted towns and cities in the UK 9. Leicester 12 micrograms per cubic metre Getty The most polluted towns and cities in the UK 8. Leeds 12 micrograms per cubic metre Getty The most polluted towns and cities in the UK 7. Chepstow 12 micrograms per cubic metre Getty The most polluted towns and cities in the UK 6. Carlisle 12 micrograms per cubic metre The most polluted towns and cities in the UK 5. Gilllingham 13 micrograms per cubic metre Philip Halling The most polluted towns and cities in the UK 4. Swansea A view of Swansea centre taken from Kilvey Hill January 2016 Getty The most polluted towns and cities in the UK 3. Manchester Manchester, UK - November 24, 2016: View of Manchester city center. Tall buildings an be seen on either side of the road and a tram can be seen passing. People can be seen walking on the pavements. Getty The most polluted towns and cities in the UK 2. Gibraltar Wide view of the rocks of gibraltar from the observation deck Getty The most polluted towns and cities in the UK 1. Scunthorpe Scunthorpe, UK - October 19, 2015. TATA steels' Scunthorpe plant in England which has recently been saved from closure after being bought by the investment firm Greybull Capitla for Â£1. Getty

A study last week linked higher rates of mental disorders in London to increasing prevalence of super-strength “skunk” cannabis, and other research makes clear that there are likely to be several factors which contribute.

In the KCL study, the first of its kind, young people living in urban areas were found to be twice as likely to have had a psychotic experience.

“This study found that psychotic experiences were significantly more common among teens exposed to higher levels of air pollution,” said Dr Joanne Newbury, lead author of the study, which was published in JAMA Psychiatry yesterday.

“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.

“This means that in areas with the highest levels of nitrogen oxides, there were 12 teens who reported psychotic experiences for every 20 teens who did not report psychotic experiences.”

Psychotic experiences are more common in early adolescence than adulthood. While they are similar to symptoms in disorders like psychosis or schizophrenia, these experiences do not automatically mean someone has a diagnosed mental health condition.

To assess this difference they used data from 2,232 young people across England and Wales who have been enrolled in a twin study at birth.

Thirty per cent of the participants reported at least one psychotic experience between the age of 12 and 18.

The researchers compared levels of key pollutants in areas where they lived, went to school or spent time at age 17, and discovered that those breathing the most toxic air had the highest odds of having had such an episode.

Nitrogen dioxide and other nitrogen oxides are key pollutants produced from car exhausts, power plants and other fumes and were studied alongside ultra-fine particles (PM2.5 and PM10), which are particularly associated with diesel vehicles.

In total, the nitrogen oxides explained about 60 per cent of the elevated risk, even after Dr Newbury and her colleagues had statistically adjusted for other factors linked to higher rates of psychosis.

Dr Helen Fisher, another of the authors, said their study provides “initial clues”.

“It’s no different from smoking and lung cancer would have been originally,” she said. “We all thought: ‘Obviously there must be an association’. But you can’t really look at that as definitive until you’ve looked at it in lots of different studies.”

Independent academics said the work was an important starting point but called for pollution exposure in other groups to be studied.

“Most evidence points to the relevance of early childhood in psychosis risk, a period the study did not cover,” said Prof Andreas Meyer-Lindenberg, from the University of Heidelberg.

Dr Daniel Maughan, associate registrar for sustainability at the Royal College of Psychiatrists, said: “While the paper has not proved air pollution causes psychosis, the findings are concerning as they suggest that increased psychosis rates in urban areas are potentially linked to air pollution.

“We need a radical approach to air pollution as it is very likely damaging the mental health of young and older people alike.”

A government spokesperson said: “Air pollution is one of the biggest public health challenges facing our country and we are taking ambitious action to cut it. We are investing £3.5bn in reducing emissions at the roadside and the World Health Organisation has praised our Clean Air Strategy as ‘an example for the rest of the world to follow’.