A new study found evidence to support the idea that air pollution may be indirectly linked to bipolar disorder.
It’s no secret that air pollution can affect physical health. But new research indicates it can also take a toll on mental health, including an increase in depression and bipolar disorder.
National Geographic reported that in the U.S., researchers have discovered that countries with poor air quality (according to the Environmental Protection Agency) had a 27% increase in bipolar disorder and a 6% increase in depression cases.
The study was led by University of Chicago geneticist Andrey Rzhetsky, who says it’s important to acknowledge that the study doesn’t prove air pollution leads to mental health problems, but does seem to add to a person’s risk. In London, China and South Korea, similar studies have indicated the same outcome.
To come to this conclusion, researchers on Rzhetsky’s team studied data from the U.S. and Denmark. In the U.S., they examined 11 years of health insurance data for 151 million individuals who had claims in four disorders: bipolar disorder, major depression, personality disorder, and schizophrenia. Epilepsy and Parkinson’s were also taken into consideration.
Next, the team studied data on country air, water, and land quality from the Environmental Protection Agency. Specifically, they paid attention to the areas where claims and poor air quality overlapped. In doing so, the strongest connection was found between pollution and bipolar disorder.
Pollution & Bipolar Disorder
The researchers also worked with scientists in Denmark. There, researchers looked at childhood air pollution exposure and connection to similar disorders. They found links between pollution and depression and bipolar disorder as well.
“These findings add to the current evidence from previous studies of a possible link between air pollution and psychiatric disorders,” Ioannis Bakolis, an epidemiologist from King’s College London who was not involved with the study, tells National Geographic.
However, Bakolis adds that too many variables exist to say there is a definitive link.
According to National Geographic, in the past scientists have gained knowledge of air pollution’s effects on the brain through studying rodents and dogs. In 2002 specifically, a study examined pollution from traffic and the impact on feral dogs and concluded that lung, nasal and brain damage were present.
“What happens in the brain is something resembling inflammation,” Rzhetsky said. “It results in symptoms that look like depression [in dogs].”
Rzhetsky notes that it’s important for mental health experts to consider environmental risk factors when it comes to treating patients, and adds that treating such disorders in a clean environment would be “the holy grail.”