Warmer winter days may be having a greater effect on the mental health of children and young adults than many people expect, according to new Australian research. Researchers found that unusually high temperatures during winter were linked to more hospital visits for mental health conditions among people aged from birth to 24 years. They also warned that these health impacts could become more common as climate change continues to raise temperatures.
The study analysed around 720,000 hospital admissions in New South Wales. It was published in the Journal of the American Academy of Child & Adolescent Psychiatry. Scientists looked at how changes in temperature affected emergency hospital presentations for mental health disorders. They found that the risk increased during both warm and cold seasons when temperatures were higher than normal. However, the strongest effects appeared during winter rather than summer.
Certain mental health conditions showed a clear rise only during the colder months. These included schizophrenia, eating disorders and deliberate self-harm. The researchers said this pattern was unexpected because many people would assume the greatest health risks would happen during the hottest days of summer.
Lead author Dr Wen-Qiang He, an epidemiologist from the University of Sydney‘s Faculty of Medicine and Health and Charles Perkins Centre, said the findings challenged common expectations.
He explained that people generally expect extreme summer heat to have the biggest impact on mental health. Instead, the research showed that warmer-than-usual winter weather was linked to the highest increase in hospital presentations among children and young adults.
Overall, heat was responsible for more than eight per cent of mental health admissions during the colder months. In comparison, it accounted for almost three per cent of admissions during warmer seasons.
The study also found that some groups were more affected than others. Female patients and young adults experienced a greater increase in risk during winter compared with other age groups.
Researchers also examined how future climate change could influence these hospital admissions. They used climate models that looked at different scenarios for greenhouse gas emissions to guess what might happen by the end of this century.
Their projections suggest that if emissions remain low, heat-related mental health admissions could increase by about six per cent during the final decade of the century. Under a medium-emissions scenario, the increase could reach almost eight per cent. If greenhouse gas emissions continue at high levels, admissions linked to heat could rise by nearly 21 per cent.
The findings come as Australia has experienced unusually warm conditions leading into winter. Several regions recorded higher-than-average temperatures, while Sydney had its warmest June since weather records began in 1859.
Dr He said these warmer winters are becoming more common because of climate change. He added that rising temperatures are already affecting the mental health of some of the country’s youngest and most vulnerable people.
He said the problem is expected to become more serious if global temperatures continue to rise. Because of these findings, governments and health systems should include mental health when planning for climate change and developing public health strategies. The researchers did not investigate exactly how higher temperatures affect mental health. However, they suggested several possible reasons.
One explanation is that heat may influence brain function and the way different parts of the brain communicate with each other. Children and young adults could be more sensitive because their brains are still developing.
Another possible reason is that people naturally expect winter to be cold. During unexpected warm periods, they may continue wearing heavy clothing or using thick blankets while sleeping. This can cause the body to become too warm, disturb sleep and place extra stress on the body’s temperature control systems.
The researchers said more studies emphasised the necessity of conducting more studies to gain a deeper understanding of to better understand these biological processes. They believe their findings highlight the need for stronger climate action and better mental health planning to protect young people as the world continues to warm.
