Climate Change Impact on Brain Disorders

Few studies have attempted to understand the effects of climate change on brain and neurological health. A team from University College London (UCL) describes in Lancet Neurology how global warming, more extreme weather conditions, and weather events can negatively affect the health of people who are already vulnerable or suffering from brain diseases.

The lead author, Dr. Sanjay Sisodiya, a professor of neurology, announces that the effects of climate change on neurological diseases will be significant. He emphasizes the urgent need to better understand the possible impact of climate change on the development and prevalence of neurological diseases, as well as the exacerbation of inequalities in brain and mental health.

The study, a literature review and meta-analysis of 332 studies published worldwide between 1968 and 2023, covered 19 different neurological conditions selected based on the Global Burden of Disease 2016 study. These included strokes, migraines, Alzheimer’s disease, meningitis, epilepsy, and multiple sclerosis (MS). The team also analyzed the impact of climate change on several other common psychiatric disorders, including anxiety, depression, and schizophrenia.

There is clear evidence of the climate’s impact on brain conditions, particularly strokes and infections of the nervous system. The analysis reveals that:

– Both extremely low and high temperatures, as well as larger or unusual temperature variations during the day, have an impact on stroke incidence.
– Nighttime temperatures, which can disrupt sleep, can also worsen a number of brain disorders.
– During periods of higher temperatures, especially during heatwaves, there is an increase in hospital admissions, disability incidence, and mortality, particularly due to more severe strokes.
– People already suffering from dementia, who are more likely to be exposed to extreme temperatures due to cognitive impairments limiting their ability to adapt their behavior, face higher risks of neurological, cerebrovascular, and cognitive disorders.
“In these patients, a low awareness of risk is associated with reduced ability to seek help or adapt to environmental factors.”

– Susceptibility worsened by frailty, multimorbidity, and psychotropic medications: thus, greater temperature variation, hotter days, and heatwaves lead to increased hospitalizations and mortality in these generally older individuals.
As the severity of adverse weather events and global temperatures increase, populations will be exposed to environmental factors more likely to affect the incidence and prevalence of brain conditions. The authors, in addition to raising awareness of the effects of climate change on the brain, advocate for research to be up-to-date and to consider not only current climate data but also model its future consequences.

The concept of climate stress itself needs to be developed to raise awareness among the medical community and healthcare systems about the risks of climate change for the brain and its implications for neurological care.