【要旨／ハイライト】
Studies have reported a strong association between policy stringency and mental health problems during the COVID-19 pandemic, primarily among females, but the causal effect of people's stay-at-home behavior on mental health is not yet known. This study evaluated how pandemic-related confinement at home affected the incidence of suicide among Japanese females. We employ a shift-share IV design, assessing whether differential exposure to the pandemic shock led to changes in the outcome variable. We found that suicide increased among females under 20 years old as more people stayed at home. The results are robust across different model specifications. Counterfactual analyses show that at least 37% of suicides in the demographic group can be attributed to home confinement. Our results suggest that a substantial part of the observed increase in suicide rates among female children and adolescents was driven by lifestyle changes during the pandemic.