Is Pollution Linked to Bipolar?

With mental health such a hot potato on the agenda of healthcare services across the world, it’s unsurprising that scientists have devoted significant research towards uncovering the reasons why conditions such as schizophrenia, depression and bipolar disorder develop.

One such study from Denmark and the USA believes it has found a direct correlation behind a higher incidence of mental illness and prolonged exposure to air pollution, especially in those of a young age. However, not everyone is convinced by the results and even the paper’s own authors are in agreement that further research is required to conclusively prove the causal link.

Current and controversial

The quality of the air we breathe has never been discussed in the mainstream media or contemplated by the man on the street as much as right now - one only need look at the success of last year's Air Quality Emissions show for evidence of the issue’s status on an international scale. Aware of this fact, a team of scientists looked at data collected from the USA and Denmark to try and establish a connection between environmental factors and poor mental health.

The study’s authors looked at the insurance claims submitted by 151 million US citizens between 2003 and 2013, cross-referencing this information against air quality measurements made by the Environment Protection Agency (EPA) over the same period. Meanwhile, they also incorporated the data provided by Danish national treatment records between 1979 and 2002, comprising 1.4 million people in total. This was mapped against the pollution information collected by national air quality monitoring networks.

The Danish data monitored fewer contaminants than the EPA’s list of 87 pollutants, but allowed for greater specificity among its subjects. This facilitated more accurate prediction of a person’s individual exposure to air pollution throughout their life, creating the opportunity to gain further insight in the paper’s conclusions.

Alarming results

Those conclusions pointed to a direct link between prolonged exposure to poor quality air and a higher incidence of psychiatric disorders in both the US and Denmark. However, the more detailed data offered by the Danish records allowed the paper’s authors to further suggest that the first 10 years of a person’s life might be the most important in terms of brain development, representing the period during which it is most susceptible (and vulnerable) to damage via air pollution that could manifest itself in undesirable outcomes in the future.

However, the authors were quick to concede that there were various other factors (such as genetic data, societal conditions and life experiences, among many others) which could feasibly contribute to the development of psychological problems and that this study alone is far from conclusive. Indeed, they even went to the unorthodox length of publishing a concurrent appraisal of the evidence alongside the original review.

“Despite analyses involving large datasets, the available evidence has substantial shortcomings and a long series of potential biases may invalidate the observed associations,” explained Professor John Ionaddis, who authored the appraisal. “More analyses by multiple investigators, including contrarians, are necessary.”