A population-based cohort to investigate the impact of COVID-19 on socioeconomic inequalities in mental health care in Italy (CoMeH): study protocol.

Purpose: The Covid and Mental Health (CoMeH) cohort was established to assess the impact of the COVID-19 pandemic on the use of mental health care services in Italy in the short and long term, with a particular focus on socioeconomic and/or citizenship inequalities.

Methods: The CoMeH cohort includes all residents for at least two years in one of three vast catchment areas (N = 5,167,043), aged ≥ 10 years and assisted by a National Health Service (NHS) general practitioner (GP) of the area of residence. Primary outcomes of interest are the following indicators of mental health care services use: first access to any mental health care service (MHCS), total number of accesses to MHCS, the consumption of psychiatric drugs, the number of psychiatric or psychological outpatient visits, the number of residential or day care days spent in psychiatric facilities, the number of emergency department (ED) admissions, and inpatient admissions to hospitals.

Results: Initial findings show that incident MHCS users were 3.2% of the population of the Bergamo Local Health Authority (LHA), 3.5% of the Rome 2 LHA, and 4.4% of the Tuscany Region. The overall crude incidence rate of access to mental health care was 3.3% in the pre-COVID-19 period and 2.6% during the pandemic. Prescriptions for a mental disorder (57.2%) and ED admissions (25.1%) were the main reasons for enrollment. Compared to the general population, people with mental health conditions were older and more often female. The distribution of the incident users by deprivation index overlapped that of the population. Immigrants were younger, socioeconomically more deprived, and more often entered the study for an ED admission.

Conclusion: This first CoMeH cohort study focused on the impact of the pandemic through the evaluation of hospitalizations, emergency department accesses, outpatient visits, residential and day care service use, and drug prescriptions. We also evaluated socioeconomic inequalities through the use of census-based deprivation index and migration status. Finally, we also analyzed the impact of COVID-19 infection and outcome on the study cohort.