A Systematic Literature Review of the Impact of Climate Change on the Global Demand for Psychiatric Services

Impact of heat on mental health emergency visits: a time series study from all public emergency centres, in Curitiba, Brazil

OBJECTIVES

Quantify the risk of mental health (MH)-related emergency department visits (EDVs) due to heat, in the city of Curitiba, Brazil.

DESIGN

Daily time series analysis, using quasi-Poisson combined with distributed lag non-linear model on EDV for MH disorders, from 2017 to 2021.

SETTING

All nine emergency centres from the public health system, in Curitiba.

PARTICIPANTS

101 452 EDVs for MH disorders and suicide attempts over 5 years, from patients residing inside the territory of Curitiba.

MAIN OUTCOME MEASURE

Relative risk of EDV (RREDV) due to extreme mean temperature (24.5°C, 99th percentile) relative to the median (18.02°C), controlling for long-term trends, air pollution and humidity, and measuring effects delayed up to 10 days.

RESULTS

Extreme heat was associated with higher single-lag EDV risk of RREDV 1.03(95% CI 1.01 to 1.05-single-lag 2), and cumulatively of RREDV 1.15 (95% CI 1.05 to 1.26-lag-cumulative 0-6). Strong risk was observed for patients with suicide attempts (RREDV 1.85, 95% CI 1.08 to 3.16) and neurotic disorders (RREDV 1.18, 95% CI 1.06 to 1.31). As to demographic subgroups, females (RREDV 1.20, 95% CI 1.08 to 1.34) and patients aged 18-64 (RREDV 1.18, 95% CI 1.07 to 1.30) were significantly endangered. Extreme heat resulted in lower risks of EDV for patients with organic disorders (RREDV 0.60, 95% CI 0.40 to 0.89), personality disorders (RREDV 0.48, 95% CI 0.26 to 0.91) and MH in general in the elderly ≥65 (RREDV 0.77, 95% CI 0.60 to 0.98). We found no significant RREDV among males and patients aged 0-17.

CONCLUSION

The risk of MH-related EDV due to heat is elevated for the entire study population, but very differentiated by subgroups. This opens avenue for adaptation policies in healthcare: such as monitoring populations at risk and establishing an early warning systems to prevent exacerbation of MH episodes and to reduce suicide attempts. Further studies are welcome, why the reported risk differences occur and what, if any, role healthcare seeking barriers might play.

[Climate change, biodiversity loss and pollution: consequences for psychiatry]

The climate crisis, loss of biodiversity and increasing global pollution are a threat to mental health. Comprehensive transformations are needed to overcome these crises, which will also affect the mental healthcare system. If done correctly these change processes can seize the chance to improve mental health while at the same time addressing the crises. This includes avoiding the need for psychiatric treatment by strengthening the focus on mental health promotion and prevention, and also considering environmental aspects when targetting therapy procedures. In addition, by focusing on nutrition, mobility and the effects of nature, patients can be empowered to increase their mental resilience whilst reducing the negative effects on the environment. At the same time, the mental healthcare system must adapt to changing environmental conditions: increasing heat waves make protective measures necessary, especially for people with mental illnesses and increasing extreme weather events can lead to shifts in the spectrum of illnesses. Appropriate funding mechanisms will have to be established to support mental healthcare throughout this transformation.