Identification of high risk groups with shorter survival times after onset of the main reason for suicide: findings from interviews with the bereaved in Japan

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.

Occurrence of Mental Illness and Mental Health Risks among the Self-Employed: A Systematic Review

We aimed to systematically identify and evaluate all studies of good quality that compared the occurrence of mental disorders in the self-employed versus employees. Adhering to the Cochrane guidelines, we conducted a systematic review and searched three major medical databases (MEDLINE, Web of Science, Embase), complemented by hand search. We included 26 (three longitudinal and 23 cross-sectional) population-based studies of good quality (using a validated quality assessment tool), with data from 3,128,877 participants in total. The longest of these studies, a Swedish national register evaluation with 25 years follow-up, showed a higher incidence of mental illness among the self-employed compared to white-collar workers, but a lower incidence compared to blue-collar workers. In the second longitudinal study from Sweden the self-employed had a lower incidence of mental illness compared to both blue- and white-collar workers over 15 years, whereas the third longitudinal study (South Korea) did not find a difference regarding the incidence of depressive symptoms over 6 years. Results from the cross-sectional studies showed associations between self-employment and poor general mental health and stress, but were inconsistent regarding other mental outcomes. Most studies from South Korea found a higher prevalence of mental disorders among the self-employed compared to employees, whereas the results of cross-sectional studies from outside Asia were less consistent. In conclusion, we found evidence from population-based studies for a link between self-employment and increased risk of mental illness. Further longitudinal studies are needed examining the potential risk for the development of mental disorders in specific subtypes of the self-employed.