Overarousal as a mechanism of the relation between rumination and suicidality.

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.