Children who lived in areas with higher levels of air pollution are significantly more likely to develop major depressive disorder until the age of 18.
In the first analysis of the impact of common air pollutants on the mental health of adolescents, researchers found that young people are three to four times more likely to have depression at the age of 18 if they were exposed to direct air at the age of 12. is a greater risk factor than physical violence, increasing the risk of adolescent depression.
Scientists said their findings are particularly important as 75% of mental health problems begin in childhood or adolescence when the brain is rapidly developing. Work also shows a link between toxic air and antisocial behavior, but more work is needed to confirm it. This year, more extensive research is expected.
"The high level of air pollution is not good for you, and especially for your children, whether it is physical or mental health," said Helen Fischer in London at Kings College, who led the study. “It is reasonable to try to avoid areas with the highest levels of air pollution. We really should encourage local and national governments to reduce these levels. ”
A study published in a psychiatric study journal brought together information from the London Children's Group with high-resolution data on air pollution levels.
Of the 284 children surveyed, the 12-year-old 25% of the most polluted children were three to four times more likely than those aged 18 to 25% of the least polluted areas. By comparison, previous work has shown that children suffering from physical abuse have more than one-and-a-half times more likely to develop depression.
Researchers took into account other factors that could affect mental health, such as family history of mental illness, income level, intimidation and smoking habits. They also expressed concern about anxiety and ADHD but found no link to air pollution.
The risk of anti-social behavior was three to five times higher. But, unlike depression, the result was not statistically significant, probably because the number of adolescents in the study was poor.
Compared to physical health, the impact of air pollution on mental health has been relatively little studied. Research on adults has so far produced controversial results, although there is strong evidence that air pollution can lead to a "significant reduction in intelligence".
The study was not designed to investigate the cause of depression in adolescents, but Fisher said the inflammation caused by toxic contamination was most likely: “We know that pollutants are small enough to cross the blood and brain barrier. [and] we know there are great links between inflammation in the brain and the development of symptoms of depression. ”
She said that children and adolescents are particularly vulnerable. "Their brains are developing, hormonal things change a lot, and they are subject to many stressful things," for example, building their relationships with the world, as well as examinations and looking for work.
Fisher said that further research was important because preventing air pollution could be less complicated than other factors that cause mental harm. "If we really understand what is happening then we have the opportunity to intervene potentially early and do something about it," she said.
"This study highlights the dangers of air pollution to UK teenagers, especially those living in urban areas," where mental health problems are greater, said public health physician Robin Russell-John.
The level of nitrogen dioxide pollution in most of the UK's cities is illegal, and contamination of small particles in many places goes beyond the guidelines of the World Health Organization. The government agrees with dirty air that shortens life and harms children, but its latest action plan for land pollution has been described as "gracious" by environmental lawyers.
Professor Chris Griffiths, founder of the Doctor's Diesel Fuel Campaign, said: "There is a need for further research, but there is an urgent need to reduce the exposure of young people to toxic air pollution."
"Revelation is truly shocking and sad and shows how critical it is that this public health crisis is being dealt with properly," said Jenny Bates, Friends of Earth.
Rebecca Daniels, the healthcare charity Medact, said: "The government's response is very inadequate – we now need a strong and comprehensive clean air policy, including drastically reducing the number of polluting vehicles on our roads."