Pollution Increases Risk of Psychotic Experiences, Study Suggests

A new study from King’s College London has found a link between prolonged exposure to poor air quality and the incidence of psychotic episodes among teenagers. Published in the scientific journal JAMA Psychiatry, the paper followed approximately 2,000 adolescents living in urban, semi-urban and rural areas of London and measured their exposure to air pollution against their experiences of psychosis.

Defined as experiences of mild mental abnormality, such as hearing voices that nobody else can or suffering from paranoia, the psychosis may be caused or exacerbated by air pollution and lead to problems in later life, though the authors of the report were quick to caution that more research is necessary before a definitive conclusion can be reached. However, its results certainly provide more evidence that more must be done to improve air quality and reduce transport-related pollution in urban settings if we are to avoid jeopardising the mental and physical health of future generations.

Inner city troubles

Nearly a third (623) of the test subjects reported having experienced at least a single psychotic episode during their teenage years. The episode could take the form of hearing voices in their head or being under the impression that someone was watching them. There was a large discrepancy between the youngsters who lived in urban settings and their ruralised counterparts, suggesting that air pollution could indeed play a part in generating psychosis in young people.

Over one third of the teenagers who lived in the most polluted areas (12 of every 32, or 37.5%) said they had suffered a psychotic experience at some point in their life. Meanwhile, that figure was just over a quarter (7 from every 27, or 25.9%) among the adolescents living in less polluted areas.

Growing evidence

The authors of the study highlighted that while its contents are far from constituting definitive proof that air pollution can trigger psychotic episodes, they do contribute to a growing body of evidence that suggests poor air quality can intensify mental disorders. It’s unclear as to whether the pollutants themselves are finding their way through the lungs into the bloodstream and then into the brain, or whether a chemical coating on the particles is having the same inflammatory effect on the body and mind.

Of course, it is also possible that other factors could be contributing to the higher rate of psychotic experiences among urban dwellers, such as the noise pollution of the environment or the heightened stress levels of city living. The authors were diligent in adjusting their results to account for other socio-economic factors such as social deprivation, substance abuse and a history of mental health in the family, but stressed they could not be sure they allowed for everything.

Further results required

Other commentators on the subject have pointed out that there are too many variables and unknowns in the study for it to be taken as conclusive proof of the link. “While this is a careful study of a large cohort, it should be borne in mind that researchers did not actually measure, but modelled, air quality and also could not know when participants were where,” explained Professor Andreas Meyer-Lindenberg from the University of Heidelberg.

“While the authors looked at many potential factors that could influence air quality and psychosis risk, such as neighbourhood socio-economic status, the findings should be replicated in a setting where pollution and location are directly measured before firm conclusions can be drawn.”