As more of the world’s population flocks to urban areas, scientists and health officials are increasingly concerned with the air pollution’s impacts on human health. In one recent study focused on mental health, scientists from King’s College London examined the association between urban living and adolescent psychotic experiences.
The results of their study, published in JAMA Psychiatry last week, reported that adolescents exposed to high levels of air pollution are in fact more likely to report psychotic experiences. Professor Frank Kelly, part of the research team at King’s College London, told The Guardian “there seems to be a link between exposure to air pollution and effects in the brain, and this is perhaps another example of this.”
The study used high-resolution air pollution data and reports of psychotic experiences disclosed by more than 2,000 adolescents from England and Wales. Study participants were members of the long-term Environmental Risk Longitudinal Twin Study, which has tracked the health of these teenagers since birth. Once each participant reached the age of 18, they were interviewed privately by researchers about psychotic experiences including delusions, hallucinations, and more severe events. Researchers asked questions such as “do you hear voices that others cannot,” and “have you ever thought you were being watched, followed, or spied on?”
At least one-third of the subjects reported having at least one psychotic experience since age 12. While this figure is consistent with what is considered normal for teenage years, the authors noticed that psychotic experiences were significantly more common among teens living in the top 25% most polluted places with exposure to nitrogen dioxide, nitrogen oxides, and small particulate matter.
Nitrogen dioxide and nitrogen oxides were responsible for 60% of the association between living in urban areas and having psychotic experiences during adolescence. Small particle pollution is responsible for the remaining percentage of reported psychotic experiences.
Nitrogen oxides from vehicles are at illegal levels in many British towns and cities. Joanne Newbury from King’s College, who led the research, told The Guardian 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.” And, “in areas with lower levels, there were only seven teens who reported psychotic experiences for every 20 teens who did not.”
While these results are an association and more research is needed to prove causation, they are alarming enough to bring attention to the burgeoning impacts that air pollution has on human health and development.