Background: No epidemiological data exists for the association between mental disorders and the risk of severe acute respiratory syndrome MESHD coronavirus 2 (SARS-CoV-2) infection MESHD and coronavirus disease MESHD 2019 (COVID-19) severity. Aims: To evaluate the association between mental disorders and the risk of SARS-CoV-2 infection MESHD infection and severe HP and severe outcomes following COVID-19. Methods: We performed a cohort study using the Korean COVID-19 patient database based on the national health insurance data. Each patient with a mental or behavioral disorder (diagnosed during six months prior to the first SARS-CoV-2 test) was matched by age TRANS, sex, and Charlson comorbidity index with up to four patients without mental disorders. SARS-CoV-2 positivity risk and risk of death MESHD or severe events (intensive care unit admission, use of mechanical ventilation, and acute respiratory distress HP syndrome MESHD) post- infection MESHD were calculated using conditional logistic regression analysis. Results: Among 230,565 patients tested for SARS-CoV-2, 33,653 (14.6%) had mental disorders, 928/33,653 (2.76%) tested positive, and 56/928 (6.03%) died. In multivariate analysis with the matched cohort, there was no association between mental disorders and SARS-CoV-2 positivity risk (odds ratio [OR], 1.02; 95% confidence interval [CI], 0.92-1.12); however, a higher risk was associated with schizophrenia HP-related disorders (OR, 1.36; 95% CI, 1.02-1.81). Among confirmed cases TRANS, mortality risk significantly increased in patients with mental disorders (OR, 1.84, 95% CI, 1.07-3.15). Conclusion: Mental disorders are likely contributing factors of mortality following COVID-19. Although the infection MESHD infection risk TRANS infection risk TRANS risk did not increase in overall mental disorders, patients with schizophrenia HP-related disorders were more vulnerable to the infection MESHD.