Associations between high concentrations of air pollution and psychiatric emergency department visits during the COVID-19 pandemic: a register-based study

Abstract

Introduction / Background: Converging results has suggested a link between increased exposure to air pollution and acute exacerbation of mental disorders such as depression, substance abuse, psychotic disorders and even suicide. However, what happens to this association during a large societal change such as the COVID-19 pandemic, remains unknown. Aim(s) / Objective(s): The aim of this study is to investigate the association between increased levels of particulate matter (PM) and number of visits to a psychiatric emergency department before and during the COVID-19 pandemic. Further, this study aims to identify if there are any specific risk groups who are more susceptible to the effects of air pollution by studying sex, age, and outpatient status. Methods: Data on number of visits to the psychiatric emergency unit at Sahlgrenska University Hospital in Gothenburg was provided by hospital administration and compared to daily levels of PM10 and PM2.5. The data was analyzed statistically using a time-stratified case-crossover design. Results: A significant association between exposure to PM10 and PM2.5 and increasing number of visits to the psychiatric emergency department could be seen during the control period for day 0-1 post exposure for females and for patients with ongoing outpatient contact. Remaining results in this study did not reach statistical significance. However, a positive association could be seen numerically for several of the analyses. For males, the age groups 18-24 and >65 years and individuals without ongoing psychiatric outpatient contact, this association seemed to increase during the pandemic. Conclusion(s) / Implication(s): Although not significant, several of the analyses indicate that there might be a positive association between increased levels of air pollution and number of visits to the psychiatric emergency department, and that this association changed during the pandemic. Additional studies on a larger population and for a longer period are needed to further explore how the pandemic has affected the suggested relationship between increased air pollution and mental illness.