Exposure to sunny, hot, and humid weather may trigger severe mental health symptoms that require emergency care. The corresponding study was published in Environmental International.
Mental disorders were estimated to be the most costly health issue in the US in 2013, costing roughly $201 billion. The global burden of mental disorders also accounts for 32.4% of years lived with disability and 13% of disability-adjusted life years.
Research also suggests that high temperatures and humidity may increase mental disorder-related emergency department admissions.
Many such studies, however, have largely focused on temperature and have paid little attention to other meteorological factors.
In the current study, researchers set out to address these knowledge gaps by examining how multiple meteorological factors, including temperature, relative humidity, heat index, and rainfall, individually and jointly affect mental disorder-related emergency department visits.
For the study, they analyzed meteorological data from every county in the borough of New York alongside data from emergency department visits in the same area between May and October 2017 and 2018. In the study periods, they recorded 547, 540 emergency department visits attributed to mental disorders in New York State.
After analyzing the data, they found that a combination of high temperature, solar radiation, and relative humidity posed the greatest risk of severe mental disorder symptoms and that effects were strongest between September and October. Males, Hispanic and African American individuals, those aged 46- 65 years old, Medicaid or Medicare subscribers, and those without insurance were most affected.
In particular, the researchers noted increased emergency department visits due to psychoactive substance use from drugs, including alcohol and opioids, when solar radiation, temperature, heat index, and humidity were high. They further noted that severe symptoms of mood disorders, including depression and bipolar disorders, coincided with less sun but higher temperatures.
“As extreme heat becomes increasingly intense and more frequent due to climate change, we can expect these changes to have adverse physiological effects on people,” said Shao Lin, senior author of the study and a professor at the University at Albany’s School of Public Health.
“Individuals with mental disorders are especially vulnerable to these changes, and our findings suggest that multiple, simultaneous weather stressors may compound health risk. Efforts to hone targeted care must take combined factors into account,” she added.
The researchers noted that while informative, their findings are limited. This comes as they could not control for air pollutants alongside confounders like personal activity patterns and air conditioner use, as well as other factors.