Hot weather has been linked to an increase in suicidal thoughts and behaviours among young Australians, new research shows, prompting calls for an overhaul of public health approaches to higher temperatures.
The number of young people in NSW presenting to hospitals for suicidal thoughts and behaviours increases with the temperature, a new analysis of emergency department (ED) presentations shows.
Researchers studied more than 55,000 suicidality presentations made by young people, aged 12 to 24, at EDs during the warmer months of November to March, from 2012 to 2019.
The analysis, published in the Australian and New Zealand Journal of Psychiatry, found ED visits by young people for suicidal thoughts or behaviours increased by 1.3% for every 1°C rise in daily mean temperature (DMT).
The increases occurred across a full range of temperatures and on single hot days, not only during heatwaves when factors like poor sleep were more likely to be an issue - said lead author Dr Cybele Dey, a psychiatrist and conjoint lecturer at UNSW Sydney.
"The impact on the very first day where the temperature is hotter than usual is just as bad as each subsequent day, and the effect starts at a more moderate temperature than expected," said Dr Dey.
"This is not about concern about climate change affecting the mental health of young people, this is about hot weather itself affecting them."
For example, on days with a 24-hour mean temperature of 21.9°C - the average DMT for the study period - there was an average of 45.7 youth suicidality presentations statewide. At that level presentations were already 4.7% higher than they would be at a cooler DMT of 18.3 °C, the state's average for spring.
By a DMT of 25.2°C, the base for a heatwave, presentations were about 9% higher than at the spring DMT, and about 15 per cent higher by a DMT of 30°C, which is reflective of extreme heat. There were 94 heatwave days over the study period.
The researchers, from UNSW, Sydney Children's Hospitals Network, NSW Ministry of Health, NSW Health, The University of Sydney and Queensland Children's Hospital, controlled for long-term trends, holiday periods and school days when analysing the data.
