A longitudinal study of psychological factors as mediators of the relationship between insomnia symptoms and suicidal ideation among young adults

Study Objectives: Prior cross-sectional studies indicate that psychological factors (eg, perceived burdensomeness, thwarted belongingness) may explain the relationship between insomnia and suicidal ideation. Longitudinal studies are needed, however, to examine how these variables may relate to one another over time. Using data collected at three time points, this study aimed to evaluate various psychological factors as mediators of the longitudinal relationship between insomnia symptoms and suicidal ideation. Methods: Young adults (n = 226) completed self-report measures of insomnia symptoms, suicidal ideation, and psychological factors (ie, disgust with self, others, and the world; perceived burdensomeness; thwarted belongingness; and loneliness) at baseline (T1), 1-month follow-up (T2), and 2-month follow-up (T3). Bias-corrected bootstrap mediation models were utilized to evaluate each T2 psychological factor as a mediator of the relationship between T1 insomnia symptoms and T3 suicidal ideation severity, controlling for the corresponding T1 psychological factor and T1 suicidal ideation severity. Results: Only T2 disgust with others and T2 disgust with the world significantly mediated the relationship between T1 insomnia symptoms and T3 suicidal ideation severity. When both mediators were included in the same model, only T2 disgust with the world emerged as a significant mediator. Conclusions: Findings indicate that disgust with others, and particularly disgust with the world, may explain the longitudinal relationship between insomnia symptoms and suicidal ideation among young adults. These factors may serve as useful therapeutic targets in thwarting the trajectory from insomnia to suicidal ideation. Research is needed, however, to replicate these findings in higher risk samples.