Is Insomnia Lonely? Exploring Thwarted Belongingness as an Explanatory Link between Insomnia and Suicidal Ideation in a Sample of South Korean University Students

Study Objectives: Suicide is a serious public health problem, and suicide rates are particularly high in South Korea. Insomnia has been identified as a risk factor for suicidal ideation; however, little is known about the mechanisms accounting for this relationship in this population. Based on the premise that insomnia can be lonely (e.g., being awake when everyone else is asleep), the purpose of this study was to examine whether greater insomnia severity would be associated with higher levels of thwarted belongingness and suicidal ideation, and whether thwarted belongingness would mediate the relationship between insomnia and suicidal ideation. Methods: Predictions were tested in a sample of 552 South Korean young adults who completed self-report measures of insomnia severity, suicidal ideation, and thwarted belongingness. Results: Greater insomnia symptom severity was significantly and positively associated with thwarted belongingness and suicidal ideation. Mediation analyses revealed that thwarted belongingness significantly accounted for the relationship between insomnia severity and suicidal ideation. Conclusions: These findings highlight the potential importance of monitoring and therapeutically impacting insomnia and thwarted belongingness to help reduce suicide risk.