Suicide ideation of individuals in online social networks

TL;DR

This study analyzes how social network structure and user characteristics relate to suicide ideation among Japanese social network users, highlighting social isolation and community involvement as key factors.

Contribution

It provides the first large-scale analysis linking social network features with suicide ideation, emphasizing the role of social isolation and community engagement.

Findings

Number of communities correlates with suicide ideation.

Low transitivity (few triangles) increases suicide risk.

Fraction of suicidal neighbors strongly predicts ideation.

Abstract

Suicide explains the largest number of death tolls among Japanese adolescents in their twenties and thirties. Suicide is also a major cause of death for adolescents in many other countries. Although social isolation has been implicated to influence the tendency to suicidal behavior, the impact of social isolation on suicide in the context of explicit social networks of individuals is scarcely explored. To address this question, we examined a large data set obtained from a social networking service dominant in Japan. The social network is composed of a set of friendship ties between pairs of users created by mutual endorsement. We carried out the logistic regression to identify users' characteristics, both related and unrelated to social networks, which contribute to suicide ideation. We defined suicide ideation of a user as the membership to at least one active user-defined community related to suicide. We found that the number of communities to which a user belongs to, the intransitivity (i.e., paucity of triangles including the user), and the fraction of suicidal neighbors in the social network, contributed the most to suicide ideation in this order. Other characteristics including the age and gender contributed little to suicide ideation. We also found qualitatively the same results for depressive symptoms.