Association between interpersonal trust, reciprocity, and suicidal behaviors: A longitudinal cohort study in South Korea

Background: South Korea has the highest suicide rate (33.5 deaths per 100,000 in 2012) among OECD countries. Previous cross-sectional studies have indicated that suicide is associated with social connectedness at the community level, but cross-sectional analyses cannot provide temporal information that might reveal causation.

Methods: Survey data from the Korea Welfare Panel Study (KOWEPS), a longitudinal dataset, measured interpersonal trust and reciprocity at the 1st wave (2006) and 4th wave (2009) surveys. These data were classified into four categories to reflect the change between the two time points: low(2006)-low(2009), low-high, high-low, and high-high levels of interpersonal trust and reciprocity. Suicidal ideation, planning, and attempt during the last year was assessed at the 7th wave(2012) survey using the following questions: “During the previous year, have you ever (1) seriously considered the attempt of suicide, (2) made a plan for suicide, and (3) attempted suicide?”. Logistic regression with robust standard error was applied to examine the association between social capital and suicidal behaviors among 9,084 participants.

Results: In this study, previous-year suicidal ideation was more common among women, older individuals, previously married, less educated, with lower household income, and having any chronic disease, disability, or depressive symptoms. After adjusting for covariates including baseline depressive symptoms and chronic disease, the low-low interpersonal trust group was more likely to experience suicidal ideation (OR: 1.69, 95% CI: 1.19–2.40) and suicidal planning (OR: 4.71, 95% CI: 1.42–15.68), but suicidal attempt was not significantly associated (OR: 6.00, 95% CI: 0.78–46.18), compared to the high-high interpersonal trust group. No significant association was observed in reciprocity analysis.

Conclusions: These findings suggest that building a community with high-level interpersonal trust could be an important strategy to prevent suicidal behaviors.