Background The objective of this study was to investigate the trend of self-injurious behavior (SIB) among persons who were directly impacted by coronavirus disease 2019 (COVID-19), especially those with pre-existing mental disorders. Methods Using the National Health Insurance Service-COVID-19 database cohort, the monthly SIB rate was calculated by COVID-19 subgroups (i.e., positive for COVID-19 test, negative for COVID-19 test, and non-COVID-19 test [control]). In addition, moderated regression analysis was utilized to examine the statistical difference of SIB (suicide attempt and non-suicidal self-injury using ICD-10 code) trend between COVID-19 subgroups and with and without pre-existing mental disorder. Results A total of 328,373 persons were included in the cohort study. Of these, 212,678 had been tested for COVID-19, and 7,713 of them were confirmed positive. During the pandemic peak, the “negative for COVID-19” group showed a large increase ( P = 0.003) in SIB rates compared to the control group, the “positive for COVID-19” group showed a decreasing trend, but not significant ( P = 0.314). Among those who were tested for COVID-19, those with pre-existing mental disorders showed an increasing trend of SIB compared to those without pre-existing mental disorders, however statistically insignificant ( P = 0.137). Conclusion Our results suggest that people who are tested for COVID-19 are at a high risk of SIB during the peak COVID-19 pandemic. Therefore, screening for suicide risk and psychological interventions is needed for these high-risk groups.

Objective: To investigate the cumulative effect of antipsychotics at different dosages on mortality in patients with schizophrenia. Methods: We analyzed data from the Korean National Health Insurance System−National Sample Cohort covering the 2002−2013 period. We used Cox regression analysis to calculate hazard ratios for mortality risks according to cumulative antipsychotic exposure levels (low, moderate, and high). Results: Our analyses revealed no significant association between antipsychotic exposure and mortality (either all-cause or cause-specific) in patients with schizophrenia. Conclusion: Our results imply that the excess mortality of patients with schizophrenia is attributable to factors other than antipsychotic usage.