Climate change directly contributes to more severe weather patterns, natural disasters, lost food production, and disappearing species. But we’re now learning that it can also impact certain health conditions. According to new neuroscience research, it may worsen symptoms of neurological disorders.
A team led by neurology professor Sanjay Sisodiya, of University College London’s Queen Square Institute of Neurology, studied 332 published neuroscience papers on the impact of climate change on brain health. The findings were published this week in The Lancet Neurology. And according to the report, the data is sufficient for the researchers to argue that several neurological conditions can worsen as the planet warms.
Researchers looked at 19 different nervous system conditions, including stroke, migraine, Alzheimer’s, meningitis, epilepsy, and multiple sclerosis (MS), as well as anxiety, depression, schizophrenia, and additional psychiatric disorders.
“There is clear evidence for an impact of the climate on some brain conditions, especially stroke and infections of the nervous system,” Sisodiya explained in a news release. “The climatic variation that was shown to have an effect on brain diseases included extremes of temperature (both low and high), and greater temperature variation throughout the course of the day—especially when these measures were seasonally unusual.”
Sisodiya also noted that higher temperatures during nighttime hours can disrupt sleep, which can be a trigger for certain brain conditions.
The increase in symptoms seems to vary based on conditions. Researchers found that seizure control gets worse for people with epilepsy and that symptoms of MS worsen during heat waves. The severity of strokes also rose in hotter temperatures, and mental health conditions like depression worsened. One report the researchers examined as part of the study showed that U.S. health insurance claims for mental health-related emergency room visits between 2010 and 2019 rose on days when the heat was extreme.
Joel Frank, a neuropsychologist, tells Fast Company that the links between weather and mental health are fairly clear. “There has been a good amount of research in both the psychology and sociology fields around seasonal and environmental change and how those times impact cognitive and mental health,” he says.
“When weather is warmer and there is more environmental activity and societal activity, individuals with mental health conditions can experience increased energy and symptoms themselves, thus possibly exasperating symptoms,” Frank says. He adds that individuals with bipolar disorder, for example, “are more likely to attempt suicide during a manic episode instead of a depressive episode.” That’s because “cognitive defects and psychological distress take energy to manifest,” therefore warmer weather leads to upticks in cognitive and mental health struggles.
While climate change has long been known to exacerbate a number of health conditions, this new report suggests that neurological disorders be added to the list. Researchers say that during warmer temperatures, adaptive strategies—drinking more water and limiting activities—can help lessen the symptoms for those suffering with neurological disorders. People with dementia or Alzheimer’s, however, will need to be helped to use adaptive behavior skills, such as wearing lighter clothing in hotter temperatures.