Abstract
Background
As global warming continues to worsen, the adverse effects of extreme high temperatures have been extensively studied, including the impact on depression. However, few studies have explored the impact of extreme high temperatures on depressive symptoms at different time scales.
Methods
We conducted a difference-in-difference analysis using data from China Family Panel Studies, which includes 108,099 samples. Depressive symptoms were measured by the Center for Epidemiological Studies Depression Scale. We identified 32 ºC as a threshold and defined the proportion of hours above 32 ºC as the metric of the exposure to extreme high temperatures.
Results
Our results found that extreme high temperatures increased depressive symptoms in both short-term and long-term. Exposure to more than one extreme high temperature hour in a day significantly increased depressive symptoms by 3.21% (95% CI: 2.08%, 4.36%). Our findings also revealed that the effects of extreme high temperature intensified over extended time periods, indicating a cumulative effect. In the subgroup analysis, the elderly (> 60 years) were more vulnerable than the young (< 36 years). Furthermore, we made predictions on the future extreme-high-temperature-induced depressive symptoms in China under different emission scenarios and found that the depressive symptoms in the Chinese population would increase by 22.83% (95% CI: 16.06%, 30.16%) by 2060 even under the most optimistic scenario.
Conclusions
Our study highlighted significant adverse effects of extreme high temperatures on depressive symptoms at different time scales, which warrants effective interventions to protect mental health from a warming climate.