The Unidirectional Relationship of Nightmares on Self-Harmful Thoughts and Behaviors

Understanding the direction of the predictive relationship between nightmares and suicidal behaviors is important to model its underlying mechanisms. We examine the direction of this relationship and the mediating role of negative affect. A fixed interval diary study obtained presleep and postsleep measures of affect, nightmares, and self-harmful thoughts and behaviors (SHTBs) from 72 university students (88.9% female). The results show predictive utility of nightmares on SHTBs-indicating a fourfold increased risk of SHTBs. Additionally, results support the suggestion of a unidirectional predictive influence (of nightmares on likelihood of SHTBs but not vice versa). Moreover, postsleep negative affect partially mediated the relationship between nightmares and postsleep SHTBs. This empirically validates assumptions of directionality for future models.