People with diagnosed mental illness are not more likely to become infected with SARS-CoV-2 than the general population according to a study in South Korea published in Lancet Psychiatry. However, people with a severe mental illness had a slightly higher risk of severe COVID-19 clinical outcomes than people without a history of mental illness.
People with mental illness generally have a higher mortality and poorer disease prognosis than the general population. The study authors wanted to learn how this applies to SARS-CoV-2 infection and COVID-19.
The large cohort study used a South Korean national health insurance claims database, which covers about 98% of the population. It also used data from National COVID-19-related registries, which included all patients who tested for SARS-CoV-2 in South Korea through services affiliated with the Korea Centers for Disease Control and Prevention (KCDC), the Health Insurance Review and Assessment Service of Korea, and the South Korean Ministry of Health and Welfare. Data included COVID-19-related outcomes and deaths. Additional data was obtained from the Health Insurance Review and Assessment Service of Korea.
The study population included adults over the age of 20 who took a SARS-CoV-2 test during the study period — January 1, 2020 through May 15, 2020. Mental illness was based on codes from the International Classification of Diseases (ICD-10).
Out of 216,418 people tested for SARS-CoV-2, 51,878 had a mental illness. The study authors matched 47,058 people without mental illness to 47,058 with mental illness in the propensity score matched cohort. After analysis, the researchers found COVID-19 in 109 (8.3%) patients without a mental illness, compared with 128 (9.7%) patients with a mental illness (fully adjusted OR 1.27, 95% CI 1.01–1.66; minimally adjusted OR 1.28, 1.01–1.65). Investigators also found that 71 (5.4%) patients without a mental illness died of COVID-19 compared with 89 (6.7%) with a mental illness (fully adjusted OR 1.38, 1.00–1.95; minimally adjusted OR 1.39, 1.01–1.95).
Limitations include the fact that the database utilized did not include medications, which may have influenced outcomes. The analysis did not adjust for factors such as smoking, obesity, and other confounding factors.
Because of their higher mortality rate, “patients with a severe mental illness showing acute respiratory symptoms should be prioritized for medical care,” the authors wrote. “Active surveillance, monitoring, and support of people at risk for chronic stress disorders, depression, anxiety disorders, psychosis, substance use, and suicide should be put in place.”
Lee SW, Yang JM, Moon SY, et al. Association between mental illness and COVID-19 susceptibility and clinical outcomes in South Korea: a nationwide cohort study [published online September 17, 2020]. Lancet Psychiatry. doi: 10.1016/S2215-0366(20)30421-1