Air pollution could help trigger psychotic experiences

Long-term exposure to high levels of air pollution can trigger or exacerbate a variety of ailments and diseases from heart disease to lung cancer. It has also been linked with Alzheimer’s, autism and intellectual disabilities.

Now we can add psychosis to the adverse effects of toxic air. That is according to the authors of a new study published in a psychiatric journal, who studied more than 2,200 children born in the United Kingdom in 1994/95 and found “significant associations between outdoor exposure to nitrogen dioxide, nitrogen oxides, and particulate matter and reports of psychotic experiences during adolescence.”

The scientists, who work at King’s College London, say exposure to nitrogen dioxide and nitrogen oxides could account for 60% of psychotic episodes experienced by adolescents in areas with significant levels of outdoor air pollution. These psychotic experiences included hearing voices and becoming paranoid. Nearly a third the teenagers surveyed said they had experienced at least one psychotic episode between the ages of 12 and 18.

In each case, the scientists compared a teen’s responses about psychotic experiences with the estimated air pollution levels to which they were exposed over a year. Of adolescents living in areas with the highest levels of nitrogen oxide 12 teenagers reported psychotic experiences for every 20 teens who said they had not had such experiences. Yet in areas with lower levels of the pollutant gas, only seven reported such experiences for every 20 who did not.

In other words, there seems to be a clear correlation between long-term exposure to airborne pollutants and the likelihood of having psychotic experiences. “The teens exposed to high levels of nitrogen dioxide, nitrogen oxides and particulate matter (PM2.5, fine inhalable particles derived from chemical smoke) had 71%, 72% and 45% greater odds, respectively, of psychotic experiences compared with those exposed to the lowest-quartile levels,” the authors note.

The study does not in itself provide conclusive proof that air pollution is responsible for triggering psychotic experiences, but it does indicate a likely correlation.

“This new research builds on increasing evidence of a likely link between air pollution and mental health issues,” says Daniel Maughan, a member of the Royal College of Psychiatrists. “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.”

The findings are in line with other recent studies, such as another one conducted in the United Kingdom whose authors found that children with intellectual disabilities were 33% more likely than their peers to live in areas with high levels of diesel particulate matter. By entering the blood stream through the lungs, airborne gases and particulate matter could affect the brain where they might have harmful effects such as by causing inflammation.

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