Counties in the US with the worst air quality have a rate of bipolar disorder 27% higher than the national average.
Prevalence of bipolar disorder was higher in the industrial east than on the west coast. Researchers surmise that pollution is the reason.
A complicated set of factors goes into the expression of bipolar disorder, and much of the scientific focus has been on genetics. However, research published in August finds that environmental factors account for 32% of the risk of bipolar disorder.
The study looked at insurance claims for bipolar disorder by county and compared the number of claims to EPA data on the environment. A significant relationship between poor air quality and high rates of bipolar disorder was established.
Also of note in the study was a 17% increase in bipolar disorder in densely populated counties, and a 22% decrease in bipolar disorder in counties with pleasant weather.
Before you move to a place with few people, little industry and really nice weather, note that the study looked only at the rate of mental illness, not on treatment outcomes.
Whereas the US study looked at results by county, a study in Denmark of people born between 1979 and 2002 was able to look at individual exposure to air pollution and find individual results.
It concluded that people in polluted areas are 29% more likely to have bipolar disorder.
It’s important to note that, although the studies used different methodology, the findings of the environmental impact of poor air quality on rates of bipolar disorder are essentially the same.
Contributing to the effects of air pollution on the brain are high rates of neurological inflammation and a decay of white matter in the brains of people exposed to air particulates.
However, while the results are astounding, researchers are not prepared to state that pollution causes bipolar disorder.
Many factors go into the onset and outcome of mental illness. Environmental factors are only a part of the story. But certainly, air quality does greatly influence rates of bipolar disorder.