Thwarted Belongingness As an Explanatory Link Between Insomnia Symptoms and Suicidal Ideation: Findings From Three Samples of Military Service Members and Veterans

Background: Although insomnia has been identified as a robust predictor of suicidal ideation and behaviors, little is known about the mechanisms by which sleep disturbances confer risk for suicide. We investigated thwarted belongingness as an explanatory link between insomnia symptoms and suicidal ideation across three military service member and veteran samples. Methods: Data were collected among United States military service members and veterans (N1=937, N2=3,386, N3=417) who completed self-report measures of insomnia symptoms, thwarted belongingness, suicidal ideation, and related psychiatric symptoms (e.g., anxiety, hopelessness). Bias-corrected bootstrap mediation analyses were utilized to examine the indirect effects of insomnia symptoms on suicidal ideation through thwarted belongingness, controlling for related psychiatric symptoms. Results: Consistent with study hypotheses, thwarted belongingness significantly accounted for the relationship between insomnia and suicidal ideation across all three samples; however, insomnia symptoms did not significantly account for the relationship between thwarted belongingness and suicidal ideation, highlighting the specificity of our findings. Limitations: This study utilized cross-sectional self-report data. Conclusions: Insomnia may confer suicide risk for military service members and veterans, in part, through the pathway of thwarted belongingness. Additional prospective studies are warranted to further delineate this model of risk. Our results offer a potential therapeutic target for the prevention of suicide, via the promotion of belongingness, among service members and veterans experiencing insomnia symptoms.