Preexisting depression and COVID-19: a cohort study on the risk of susceptibility and hospitalization.

Background: Depression can have negative effects on a person's physical health. However, the available evidence on the risk of susceptibility to COVID-19 and its adverse outcomes in people with mental disorders, including depression, is limited and inconsistent. Therefore, we investigated the relationship between major depressive disorder (MDD) and the risk of susceptibility to COVID-19 infection and hospitalization. The data used in the study were obtained from the Employees' Health Cohort Study of Iran (EHCSIR).

Methods: We conducted a cohort study that included 3355 participants who had complete data on major depressive disorder at baseline assessment and two annual telephone follow-ups between January 2020 and March 2022. Trained psychologists used the Persian version of the Composite International Diagnostic Interview (CIDI-2.1) to identify major depressive disorders during the baseline assessment. We applied log binomial regression models to adjust for sociodemographic factors and background health conditions.

Results: We found that 11.4% of participants had lifetime MDD and 7.3% had MDD in the past 12 months. During the pandemic, 26.1% of participants were infected with COVID-19, and 14.4% of those who were infected were hospitalized. The risk of susceptibility to COVID-19 infection was significantly higher among participants with lifetime MDD than among those without MDD (adjusted risk ratio (ARR) = 1.24, 95% CI: 1.06-1.47). However, lifetime MDD or 12-month MDD was not independently associated with hospitalization among COVID-19 cases.

Conclusions: Preexisting major depressive disorder may increase the risk of susceptibility to COVID-19.