Exploring characteristics of increased suicide during the COVID-19 pandemic in Japan using provisional governmental data

Abstract

Background: The Japanese age-standardised death rate of suicide (SDR) had decreased during 2009-2019, but increased in 2020-2021, during the COVID-19 pandemic.

Methods: This study aimed to explain the trend change in the SDR during the pandemic, disaggregated by prefecture, gender, suicide method and household, as compared to predicted SDR derived from pre-pandemic data, using linear mixed-effect and hierarchical linear regression models with robust standard error analyses.

Findings: The SDR was lower during March-June 2020 (during the first wave of the pandemic), but higher during July-December 2020 than the predicted SDR. In 2021, males' SDR was nearly equal to the predicted SDR, whereas females' SDR in the metropolitan-region (17.5%: 95% confidence interval: 13.9-21.2%) and non-metropolitan-region (24.7%: 95% confidence interval: 22.8-26.7%) continued to be higher than the predicted SDR. These gender- and region-dependent temporal fluctuations of SDR were synchronised with those of SDRs caused by hanging, at home and single-person-households. Additionally, the rising number of infected patients with the SARS-CoV-2 and polymerase chain reaction (PCR) diagnostic examinations were positively (β = 0.024) and negatively (β =-0.002) related to the SDR during the pandemic, respectively.

Interpretation: Japanese suicide statistics have previously established that the predominant method and place of suicide were by hanging and at the individual's home, respectively. The present findings suggest that transformed lifestyles during the pandemic, increasing time spent at home, enhanced the suicide risk of Japanese people by hanging and at home.

Funding: Regional Suicide Countermeasures Emergency Enhancement Fund of Mie Prefecture (2021-40).

Keywords: COVID-19; Gender; Japan; Prefecture; SDR, age-standardised death rate of suicide; Suicide mortality.

Figure 1

Fluctuations of monthly SDR during COVID-19 pandemic (2020–2021) of males+females (A,B,C), males (D,E,F) and females (G,H,I) compared to the predicted SDRs in the 47 prefectures (A,D,G), Metropolitan-region (B,E,H) and non-Metropolitan-region (C,F,I). Dotted, blue and red lines indicate the average of predicted SDR, observed SDR in 2020 and 2021, respectively. Brown areas, blue and red bars indicate the 95% confidence intervals (CI) of predicted SDR, observed SDR in 2020 and 2021, respectively. Ordinates indicate the SDR (per 100,000 people), and abscissas indicate the month. * p < 0.05, significant change of monthly SDR compared to predicted SDR using a linear mixed-effects model with Scheffe's post-hoc test. ↑and↓indicate increasing and decreasing annual SDRs compared to predicted SDRs, respectively.

Figure 2

Fluctuations of monthly hanging-SDR (A,B), charcoal-burning SDR (C,D) and SDR at home (E,F) of males during COVID-19 pandemic compared to the predicted SDRs in Metropolitan- (A,C,E) and non-Metropolitan- (B,D,F) regions. Dotted, blue and red lines indicate the average of predicted SDR, observed SDR in 2020 and 2021, respectively. Brown areas, blue and red bats indicate the 95% confidence intervals of predicted SDR, observed SDR in 2020 and 2021, respectively. Ordinates indicate the SDR (per 100,000 people), and abscissas indicate the month. * p < 0.05, significant change of monthly SDR compared to predicted SDR using a linear mixed-effects model with Scheffe's post-hoc test. ↑and↓indicate increasing and decreasing annual SDRs compared to predicted SDRs, respectively.

Figure 3

Fluctuations of monthly hanging-SDR (A,B), charcoal-burning SDR (C,D) and SDR at home (E,F) of females during COVID-19 pandemic compared to the predicted SDRs in Metropolitan- (A,C,E) and non-Metropolitan- (B,D,F) regions. Dotted, blue and red lines indicate the average of predicted SDR, observed SDR in 2020 and 2021, respectively. Brown areas, blue and red bats indicate the 95% confidence intervals of predicted SDR, observed SDR in 2020 and 2021, respectively. Ordinates indicate the SDR (per 100,000 people), and abscissas indicate the month. * p < 0.05, significant change of monthly SDR compared to predicted SDR using a linear mixed-effects model with Scheffe's post-hoc test. ↑and↓indicate increasing and decreasing annual SDRs compared to predicted SDRs, respectively.

Figure 4

Fluctuations of males (A,B,E,F) and females (C,D,G,H) monthly SDR of multiple- (A-D) and single-person household residents (E-H) during COVID-19 pandemic compared to the predicted SDRs in Metropolitan- (A,C) and non-Metropolitan- (B,D) regions. Dotted, blue and red lines indicate the average of predicted SDR, observed SDR in 2020 and 2021, respectively. Brown areas, blue and red bats indicate the 95% confidence intervals of predicted SDR, observed SDR in 2020 and 2021, respectively. Ordinates indicate the SDR (per 100,000 people), and abscissas indicate the month. * p < 0.05, significant change of monthly SDR compared to predicted SDR using a linear mixed-effects model with Scheffe's post-hoc test. ↑and↓indicate increasing and decreasing annual SDRs compared to predicted SDRs, respectively.