Abstract
Rumination, particularly brooding, is associated with suicidal ideation and attempts; however, mechanisms of these associations have not been identified. The present study examined manifestations of overarousal—agitation, insomnia, and nightmares—that have been linked to both rumination and suicide as indirect indicators of the link between brooding and suicidal ideation/attempts. A sample of 492 psychiatric outpatients (64.2% female), aged 17–65 years (M = 26.75, SD = 10.32), completed self-report measures before their intake appointments with a therapist. Results indicated that agitation and nightmares, but not insomnia, each significantly explained the association between brooding and suicidal ideation and between brooding and the presence of a past suicide attempt. Overall, these findings provide evidence that certain types of overarousal may serve as a mechanism of the association between brooding and suicidal ideation and attempts. Clinical implications, limitations, and future research directions are discussed.