The association between economic uncertainty and suicide in Japan by age, sex, employment status, and population density: an observational study.

Background: Suicide is one of the ten leading causes of death globally, and previous research has revealed a link between economic conditions and mental health. However, the literature has focused primarily on recessions and unemployment, i.e. actual economic developments, as opposed to uncertainty, which relates to economic developments that have not (yet) materialised. This study examines the differential association between economic uncertainty and suicide in Japan, depending on age, sex, employment status, and population density, in order to identify the groups that are affected the most. Methods: Using monthly prefectural suicide mortality data from the Ministry of Health, Labour and Welfare and a monthly economic uncertainty index for the period 2009 to 2019, we employed a fixed effects panel data approach to examine the association between uncertainty and suicide by population group. Findings: We found that a 1% increase in economic uncertainty is associated with a 0.061 increase in the monthly number of suicides per 100,000 people per prefecture, on average (coefficient: 6.08; 95% CI: 5.07-7.08), which constitutes a 3.62% increase. Self-employed people, as well as men in their 50s and unemployed men, experience the highest additional risk of suicide when uncertainty increases. The association was approximately three times stronger for males than for females, and a strong association was observed for self-employed males living in more densely-populated areas. Interpretation: Uncertainty appears to relate to suicides for most groups, but self-employed people, males, and those living in more densely populated areas appear to be more at risk of suicide in periods of increased economic uncertainty. Our results provide an indication of which groups mental health services and prevention strategies can focus on in times of economic uncertainty. Funding: None.