Pandemic-time mental health surveillance among the French population using survey and routine data

Alerted by the scientific community about a possible negative impact of the COVID-19 epidemic on population's mental health, Santé publique France (the French public health agency) started a reactive surveillance in March 2020. From a crisis management perspective, the objective was to closely monitor mental health developments during the pandemic and to collect necessary information to implement preventive and protective interventions for the population. The population mental health surveillance was mainly based on two data sources: first, the Coviprev survey, a declarative internet-based survey among the adult population ran weekly and then monthly during the pandemic, and second, the OSCOUR® database, developed after the heat wave of summer 2003 in France, which has been collecting daily emergency department (ED) data for almost 20 years. 94% of French ED visits are collected by the system. The main indicators monitored were mood disorders, anxiety disorders, suicidal ideation and behaviors. This surveillance confirmed, from the start and throughout the epidemic, the negative impact of the health crisis on the population's mental health and suggested that adolescents (aged 11 to 17 years) and young adults (aged 18 to 24 years) have been more affected than the rest of the population. In comparison to previous years, significant increases of mood disorders and suicidal behaviors were observed in both data sources in the beginning of 2021 and are still observed in 2023 for some indicators. The results of the work carried out showed the importance of a continuous surveillance of mental health during a crisis situation based on reactive data sources which are essential tools for steering preventive responses and advocating for the strengthening of mental health prevention and promotion policies. Strengths and limitations of the implemented surveillance system integrating two different data sources will be discussed.