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Loneliness Has a Strong Impact on Suicidal Ideation among Japanese during the COVID-19 Pandemic

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Researchers from the University of Tsukuba analyzed the degree of influence of social isolation, loneliness, and depression on suicidal ideation during the COVID-19 pandemic using data from a large-scale national questionnaire survey. The results revealed that loneliness had a direct and stronger impact on suicidal ideation than economic hardship and social isolation. It also indirectly affects suicidal ideation through depression.

Tsukuba, Japan—During the COVID-19 pandemic period, mental health of the human population remarkably deteriorated worldwide. With the spread of the infection, the number of suicides in Japan began to increase in 2020, for the first time in 11 years, and has shown no signs of decrease to date. This increasing suicide rate is due to the fear of infection, economic problems such as unemployment, and worsening social isolation, including loneliness, due to quarantine and social distance. However, there is a lack of consensus regarding these factors which affect the desire to live (suicidal ideation) and how they affect this ideation.

In this study, we analyzed the impact of social isolation, loneliness, and depression on suicidal ideation using data from a large-scale national survey by the Japan Assessment of Social and Health Inequalities due to the COVID-19 Study (JACSIS study). The survey included data of 26,000 people that was collected in February 2021. The data for men and women were analyzed separately, and prevalence rates were calculated after adjusting for age and economic status.

The results showed that 15% of men and 16% of women had suicidal ideation, with 23% of men and 20% of women having suicidal ideation only after the pandemic period. Loneliness was found to strongly affect suicidal ideation both directly and indirectly through depression compared to economic hardship or social isolation. This indicates that psychological support should be provided as a measure against isolation and loneliness and also as a measure against suicide to those who feel lonely .

This study was funded by the Japan Society for the Promotion of Science (JSPS) KAKENHI Grants (Grant Nos. 18H03062, 19K22788 and 21H04856), a JSPS Grant- in- Aid for Young Scientists (Grant No.19K20171), the Japan Health Research Promotion Bureau Research Fund (2020- B- 09) and the Research Institute of Science and Technology for Society of Japan Science and Technology Agency (JST- RISTEX), 'SOLVE for SDGs: Social Isolation & Loneliness (FY2021-)' (Grant No. JPMJRX21K2). The sponsors had no role in data collection and interpretation of our data. Findings and conclusions of this article are the sole responsibility of the authors and do not represent the official views of the research funders.

Original Paper

Title of original paper:
Impact of loneliness on suicidal ideation during the COVID-19 pandemic: findings from a cross-sectional online survey in Japan
BMJ Open


Professor TACHIKAWA Hirokazu
Department of Disaster and Community Psychiatry, Institute of Medicine, University of Tsukuba

Associate Professor MATSUSHIMA Midori
Institute of Humanities and Social Sciences, University of Tsukuba

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