ABSTRACT
This study estimates the association between emergency department (ED) visits for mental health disorders (MHDs) and the health context of the COVID-19 pandemic in the French region of Nouvelle-Aquitaine. This retrospective study took place between 2018 and 2021 using ED data. We defined the main exposure according to five periods: "Pre-pandemic (reference)", "First lockdown", "Second lockdown", "Third lockdown", and "Pandemic out-of-lockdown." We constructed the daily indicators for each MHD-related ED visit based on medical diagnoses. We described and then modeled the daily time series using generalized additive models with a quasi-Poisson regression. The analysis included 5,693,341 ED visits of which MHDs accounted for 4%. We observed a decline in ED use for most indicators, particularly during the first lockdown. Models revealed a statistically significant relative increase in ED visits for almost all MHDs during the first lockdown; for anxiety and child psychiatric disorders during the second lockdown; and only for child psychiatric disorders during the pandemic out-of-lockdown period. The public health crisis and lockdowns associated with the COVID-19 pandemic have been important sources of stress that could partially explain the deterioration of MHD indicators, thus leading to new public health concerns (notably among the youngest age group). Mental health is a major determinant of overall health and should therefore be considered in the management of crises that may require similar responses in the future.