Pandemics and pre-existing mental illness: A systematic review and meta-analysis

Pandemics are known to affect mental health of the general population and various at-risk groups like healthcare workers, students and people with chronic medical diseases. However, not much is known of the mental health of people with pre-existing mental illness during a pandemic. This systematic review and meta-analysis investigates, whether people with pre-existing mental illness experience an increase in mental health symptoms and experience more hospitalizations during a pandemic.

A systematic search was conducted in the EMBASE, OVID-MEDLINE and PsycINFO databases to identify potentially eligible studies. Data were extracted independently and continuous data were used in calculating pooled effect sizes of standardized mean difference (SMD) using the random-effects model.

Of 1791 records reviewed 15 studies were included. People with pre-existing mental illness have significantly higher psychiatric symptoms, anxiety symptoms and depressive symptoms compared to controls during a pandemic with pooled effect sizes (SMD) of 0.593 (95% confidence interval (CI) 0.46 to 0.72), 0.616 (95% CI 0.49 to 0.73) and 0.597 (95% CI 0.38 to 0.80) respectively. Studies also found a reduction in psychiatric hospitalizations and utilization of psychiatric services during pandemics.

The review highlights the need for mental health services to address the increased mental health symptoms in people with pre-existing mental illnesses during a pandemic. Future research should focus on better designed controlled studies of discrete illness groups, so as to provide a robust basis for policy makers to plan appropriate level of support and care for people with mental illness during a pandemic.