Aims: The reported increase in the number of suicides in Japan following the COVID-19 pandemic raises concerns about its impact on highly vulnerable people. In this study, we conducted a retrospective study to identify risk factors for suicide-related behaviors specific to the COVID-19 pandemic among patients who had been seen by a psychiatrist.
 Methods: Patients seen by psychiatrists at the Department of Psychiatry, Hokkaido University Hospital who had suicide-related events between April 23,2004, and December 31,2019, were classified into a pre-COVID-19 pandemic group, and those who had suicide-related events between April 1,2020, and August 31,2021, were classified into a sub-COVID-19 pandemic group. Background factors, diagnoses, and methods of suicide-related behavior of these two groups were compared.
 Results: There were 65 cases in the pre-COVID-19 pandemic group and 23 cases in the sub-COVID-19 pandemic group. There were no significant differences in background factors or diagnoses. Comparison with M. I. N. I. tests performed at the first visit showed suicidal ideation and decreased interest were common features pre-and sub-COVID-19. Meanwhile, panic attacks were more common in the sub-COVID-19 than pre-COVID-19, and the generalized anxiety was less common in the sub-COVID-19 than pre-COVID-19. Significant differences were found between the methods of suicide attempts between the pre- and sub-COVID-19 pandemic groups. Drug overdoses decreased from 44.6% to 21.7% and suicides by hanging from 26.2% to 13.0%, whereas jumping increased from 13.8% to 26.1%. Moreover, intentional traffic-related injury, poisoning, and carbon monoxide poisoning also occurred in the sub-COVID-19 pandemic group.
 Discussion: Suicide-related behaviors were more varied during the COVID-19 pandemic, with suicide-related behaviors being observed in ways that were rarely observed prior to the COVID-19 pandemic. In view of suicide prevention, limiting access to the means of suicide attempts is an effective method. Our findings suggest that there were changes in the means of suicide attempts under the COVID-19 pandemic; thus, suicide prevention measures need to be revised.
 Authors' abstract