Heat exposure associated with mental illness, study shows

A mental hospital-based study in Hanoi, Vietnam looked at if there is a relationship between heat exposure and mental health problems. The results showed significant increase in hospital admissions for mental illnesses during periods of heatwaves, especially during longer periods of heat exposure. This is according to a doctoral thesis from Umeå University.

The study, which looked at admissions data from the Hanoi Mental Hospital during a 5 year period (2008 – 2012), also found that factors including old age, gender and rural-dwelling contributed to more mental illness among vulnerable and susceptible groups during heat or extreme heat exposure.

According to the results:

• The number of admissions for mental disorders increased during hot weather such as summer season and heatwave events with mean temperature of over 35 degrees Celsius for at least 3 or 7 consecutive days.
• The risk of mental disorders among general population during heatwaves of at least 7 consecutive days was as twice as big as that during heatwaves of at least 3 consecutive days.
• There was an increase by 24 percent of cases for mental disorders in summer compared to winter.
• There was an increase by 2 percent of admissions when mean temperature went up one degree Celsius.

"I was surprised to find that there were quite strong associations between hospital admissions for depression and other mental disorders and periods of elevated temperatures or heatwaves. The associations grew stronger with the length of the heatwaves and the elderly in particular appeared more sensitive to seasonality, hot weather and heatwaves," says Trang Phan Minh, doctoral student at the Department of Public Health and Clinical Medicine, Epidemiology and Global Health unit, at Umeå University.

Trang Phan Minh's study is formative and may pave a way for future studies in Vietnam. According to the researcher, the results can assist mental health professionals in Vietnam by providing more information about the mental health impacts of exposure to weather patterns and extreme heat/heatwave.

"As the global warming phenomenon emerges and mean temperatures increase, these results showing an association between heat and mental health problems could help Vietnamese policymakers and health managers. This scenario requires good preparedness and solutions for managing a potential increased in mental disorders and for protecting poor populations and poor health groups," says Trang Phan Minh.