The Temporal Dynamics of Sleep Disturbances, Depression, and Self-Injurious Thoughts and Behaviors in Preadolescents: A Year-Long Intensive Longitudinal Study.

Despite research exploring preadolescent mood disorders, the ability to predict increases in depression severity and risk for self-injurious thoughts and behaviors (SITBs) remains poor, leaving clinicians few markers to predict increases in individual risk. One promising area of research has focused on sleep disturbances as an acute and proximal risk factor for depression and SITBs. However, little of this research has focused on children prior to adolescence or incorporated designs that enable us to disentangle the directionality of the associations between these constructs. The current study explored the temporal dynamics and directionality of the association between sleep disturbances and psychological symptoms, including depression, suicidal thoughts, and self-harm behaviors in a sample of preadolescents enriched for a history of early childhood mood disorders. Participants completed weekly electronic assessments for one year to examine week-by-week associations between sleep disturbances (i.e., trouble sleeping and fatigue) and depression, suicidal thoughts, and self-harm behaviors. Both trouble sleeping and fatigue were found to predict and precede increased depression severity, and trouble sleeping predicted endorsement of self-harm behaviors the following week, even when controlling for prior depression severity and self-harm behaviors, respectively. There was no evidence for the reverse association (i.e., depression severity or self-harm behaviors predicting subsequent sleep disturbances). Our findings provide the first evidence for a temporal and directional association between sleep disturbances and subsequent depression severity and self-harm behaviors in preadolescents. These findings highlight the potential utility targeting sleep within existing treatments for depression and self-harm behaviors in preadolescents.