University of Sydney Study Links Extreme Heat to Increased Youth Mental Health Admissions
An exclusive study conducted by the University of Sydney reveals that extreme high temperatures during warmer months double the risk of young people being admitted to hospital for mental health conditions.
The research analyzed 720,000 hospital admissions in New South Wales for individuals aged up to 24 years and indicated that the climate crisis is likely to exacerbate the already declining mental health among young people.
With global heating causing more frequent extreme temperatures, the study projects that heat-related hospital admissions will rise by at least 6% and up to 7.7% by the end of the century.
The lead author, Dr Wen‑Qiang He from the University of Sydney, stated:
"We found that as temperatures increase, we see admissions for these younger populations increase significantly. The risk doubles in the warm season and triples in the cold season.
That’s important for us to know and, if we can let the community know what’s happening, then we can prepare and help our children and young people."
The research examined 720,000 hospital admissions between 2001 and 2022 involving young people aged up to 24 years admitted for a variety of mental health conditions.
These serious admissions, which required hospitalisation rather than just emergency department visits, included mental health disorders such as schizophrenia, depression, substance misuse, eating disorders, and self-harm.
Researchers observed that when daily average temperatures were within the highest 1% for that day, the risk of hospital admission doubled during warmer months (October to March) and tripled during cooler months.
Previous studies have also linked hotter-than-average days with increased mental health admissions.
The National Climate Risk Assessment released last year highlighted that extreme heat is associated with "higher rates of suicide and mental health-related hospital admissions," citing research that points to "heightened stress, anxiety, and aggravation of psychiatric conditions."
The new study did not investigate the specific reasons behind the correlation between higher temperatures and increased mental health hospital admissions, but the authors proposed several possible explanations.
During warmer months, when absolute temperatures are higher, evidence from other studies suggests direct effects on brain function, which can negatively impact mental health.
Unexpected temperature fluctuations, such as those experienced in winter, may affect individuals' stress management, sleep patterns, and mood.
Dr Cybele Dey, an adolescent psychiatrist in Sydney and co-author of the study, noted:
"The data showed there was little lag between the temperature spikes and the hospital admissions, which suggested the heat was causing a ‘physiological’ response.
These are not mild presentations. There has to be a lot going wrong for a person to be admitted."
"Climate change is already impacting children and young people’s mental health in multiple ways. This is not the first study to show a link between unusually warm temperatures and children being admitted to hospital with mental disorders."
Dr Hasini Gunasiri, a research fellow at the Melbourne-based youth mental health research institute Orygen, who was not involved in the study, emphasized the practical implications of these findings for caring for young people.
Gunasiri explained that during periods of extreme heat, young people might resort to alcohol or other substances to cope with discomfort, irritability, sleep disruption, or emotional distress.
Heat can also increase impulsivity and risk-taking behaviors, which may elevate thoughts of self-harm.
She stated:
"Sleep disruption may be especially relevant here. Poor sleep is a well-established risk factor for suicidal ideation and self-harm in young people."
Gunasiri pointed out that current heat-health policies primarily focus on physical health outcomes such as heatstroke, dehydration, and cardiovascular illness, especially among older adults.
She suggested that mental health considerations should be integrated into planning for extreme temperatures, particularly for children and young people.
Furthermore, she recommended incorporating mental health messaging into heat warnings to raise awareness among clinicians and families about the potential mental health impacts of heat.
