Japan has a chronically high suicide rate and social phenomena with a strong negative impact tend to cause a rapid increase in the suicide rate. Increases in the suicide rate were found among middle-aged males in 1998 following the `Yamaichi shock' economic crisis, and among females and younger people during the `corona shock' period in 2020. The increase of suicide was not universal, and there have been no reports so far indicating a surge in suicide rate since 2020 except in Japan. Possible causal factors of the rapid increase were that the psychological threshold for suicidal behavior is low among Japanese, and they are more likely to perform a suicidal act in a mild depressed state.
 In terms of suicide prevention, it is important to detect depression of all levels of severity early and offer treatment and care for those with mild depression. The network of general practitioners and psychiatrists can promote appropriate care for depression. The education of healthcare professionals, particularly psychiatric professionals, is necessary to deal with suicidal ideas. Education and information are necessary as interventions to heighten the psychological threshold for suicide.
 Author's abstract