A large-scale Australian study has found that extreme heat significantly raises the risk of hospital admissions for mental health conditions among children and young people, adding urgent scientific weight to concerns about climate change's toll on psychological wellbeing. The research, led by the University of Sydney, analysed 720,000 hospital admissions in New South Wales involving individuals aged up to 24 between 2001 and 2022.

Key Findings

When temperatures reached the top 1 per cent of recorded highs, the risk of mental health-related hospital admissions doubled during warmer months and tripled during cooler months. The study was published in the Journal of the American Academy of Child and Adolescent Psychiatry and captures only the most severe cases — those requiring inpatient admission — including depression, schizophrenia, substance misuse, eating disorders, and self-harm. Emergency and outpatient visits were excluded, meaning the true burden on the health system is likely higher.

What Researchers Said

'Climate change is already impacting children and young people's mental health in multiple ways,' said Cybele Dey, an adolescent psychiatrist with the Sydney Children's Hospitals Network and co-author of the study. Her remarks were reported by Guardian Australia on Tuesday, 7 July.

Researchers attributed the rapid surge in admissions following heat spikes to a likely physiological response. Proposed mechanisms include sleep disruption, elevated stress, altered brain function, and increased impulsivity, as well as heightened use of alcohol and other substances during extreme heat events.

Projected Rise by End of Century

The study projects that heat-related mental health admissions among youth could climb by 6 per cent to 7.7 per cent by the end of the century as global temperatures continue to rise. This trajectory places the findings squarely within the broader climate-health literature linking warming temperatures to deteriorating public health outcomes — not just physical, but psychological.

Why This Matters for Health Policy

The researchers underscored the need to incorporate psychological risk into heat-health planning and policy frameworks — an area that has historically focused on cardiovascular and respiratory conditions. This comes amid growing international recognition that mental health infrastructure is underprepared for climate-driven shocks. Notably, the study's scope — spanning over two decades and nearly three-quarters of a million admissions — makes it one of the most comprehensive analyses of its kind in the southern hemisphere.

As heatwaves grow more frequent and severe under climate projections, health systems globally will need to account for the compounding mental health burden on younger populations.