Understanding depressive rumination from a mood-as-input perspective: effects of stop-rule manipulation.

The current study tested the mood-as-input hypothesis account of perseverative rumination in 25 participants with a diagnosis of major depressive disorder and 25 healthy controls. It also examined the factors underlying mood changes within a bout of rumination and their relations with trait rumination and metacognitive beliefs about rumination. A structured rumination interview was used to facilitate participants' reflection on two previous depressive incidents while deploying a specific stop-rule for the task (either a goal-guided or feeling-guided stop-rule). As predicted by the mood-as-input hypothesis, perseveration exhibited by depressed participants was affected by the interaction between diagnosis and stop-rule, with levels of perseveration being greatest when depressed participants used the goal-guided stop-rule. Increases in negative mood over the rumination interview were shown to be influenced only by participants' diagnostic status, regardless of their stop-rule. Compared to healthy controls, depressed participants also reported a preferential use of the goal-guided stop-rule in response to negative mood states in their daily lives. The findings about the dependence of rumination on stop-rule use within the depressed sample support the use of metacognitive treatment approaches in which patients are encouraged to challenge negative beliefs about the controllability of rumination.