Air pollution may be linked to bipolar disorder and depression, according to a study recently published in PLOS Biology Journal. Researchers examined the health data of millions of patients in the United States and Denmark and found that patients exposed to poor quality air were more likely to be diagnosed with each of these conditions.
Research conducted on dogs and rats had previously shown that air pollution can cause brain inflammation and symptoms resembling depression, and scientists say it is likely that human brains can be exposed to pollution in similar ways.
Some critics claim that this study raises an “intriguing possibility” in linking air pollution to psychiatric disorders but fails to make a clear case. Besides bipolar disorder and depression, the study also tested for links between pollution and schizophrenia, personality disorder, epilepsy, and Parkinson’s disease, and failed to find a significant correlation.
While potential links between pollution and mental health remain largely unexplored, the negative effects of air pollution on physical health have long been known. According to the World Health Organization, air pollution causes about 3.8 million premature deaths annually through heart disease, stroke, respiratory illnesses, and cancers.
Air pollution has grown worse in most low and middle-income cities over the past several years as demand for power and the use of private motor vehicles have increased, putting many people at risk of long-term health problems.
The report, titled “Medical Alert! Climate Change is Impacting our Health” was written by medical doctors, including allergists, pediatricians, infectious-disease doctors, OB/GYNs and gerontologists from eleven health organizations.
Very few Americans, less than 32 percent, can name a specific way in which climate change harms human health. “Doctors in every part of our country see that climate change is making Americans sicker,” said Dr. Mona Sarfaty, the director of the new consortium.
The authors broke down the specific health effects of climate change in each region of the U.S. The doctors explain that three by-products of climate change will directly impact human health: air pollution, extreme heat and extreme weather events. Increased temperatures associated with climate change intensify smog, wildfires and pollen production, leading to poor air quality, the report said. “Poor air quality increases asthma and allergy attacks, and can lead to other illnesses, hospitalizations, and deaths,” the authors wrote.
Rising global temperatures cause more frequent, longer, and more extreme heat waves in many parts of the U.S. Excessive heat leads to heat-related illness, exacerbates some medical conditions, and can cause death due to heat-stroke and dehydration. The report read, “Anyone can be harmed by extreme heat, but some people face greater risk. For example, outdoor workers, student athletes, city dwellers, and people who lack air conditioning (or who lose it during an extended power outage) face greater risk because they are more exposed to extreme heat.”
The physicians pointed out that extreme weather events are also taking a toll on their patients. The increased frequency and severity of major storms, floods, and droughts can cause injury, displacement and death, the report read. These events often prevent residents from receiving proper medical care due to blocked roads, destroyed bridges and the like. Gastrointestinal illness and disease often follow the power outages associated with extreme weather events as well, according to the doctors.
Beyond these direct impacts, climate change also speeds up the spread of infectious diseases and has an insidious impact on humans’ mental health. With temperatures rising around the world, infectious disease vectors like ticks, mosquitoes and fleas can now survive in regions that were previously too cold for them. For example, “Ticks that carry Lyme disease have become more numerous in many areas and have expanded their range northward and westward,” the report said.
U.S. residents that have experienced increasingly common extreme weather events like foods, major storms, and droughts are likely to suffer mental health consequences including post-traumatic stress disorder (PTSD), depression, and anxiety. Anyone could experience these effects, but women, pregnant women, the elderly, children, and those with a preexisting mental health condition are most at risk.
The report concluded with a call to government leaders, asking them to address climate change in the name of human health. It read, “Doctors agree with climate scientists: the sooner we take action, the more harm we can prevent, and the more we can protect the health of all Americans.”